Network hub, transfer method, and onboard network system

ABSTRACT

A hub is connected to first and second networks where first-type and second-type frames are transmitted following first and second communication protocols. The hub sequentially receives each of the first-type and second-type frames, and stores data in first and second reception buffers. If the destination of data stored in the first and second reception buffers is the first network, the hub stores the data in a first transmission buffer. If the destination is the second network, the hub stores the data in a second transmission buffer. If the first transmission buffer is a priority transmission buffer, the hub transmits priority data in the first transmission buffer with priority over non-priority data in the second transmission buffer, which is a non-priority transmission buffer.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 16/188,330,filed Nov. 13, 2018, which is a continuation of International PatentAppl. No. PCT/JP2017/015818, filed Apr. 20, 2017, which claims thebenefit of U.S. Provisional Patent Appl. No. 62/342,528, filed May 27,2016, and priority to Japanese Patent Appl. No. 2017-061914, filed Mar.27, 2017. The entire disclosure of each of the above-identifieddocuments, including the specification, drawings, and claims, isincorporated herein by reference in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to message processing technology forrelaying messages over an onboard network system including multiplenetwork that have properties different from each other.

2. Description of the Related Art

Japanese Unexamined Patent Application Publication No. 2016-111477describes a gateway that relays messages between devices conforming tothe CAN protocol and devices conforming to the Ethernet (registeredtrademark) protocol and so forth.

SUMMARY

Further improvement has been needed with the above related art.

In one general aspect, the techniques disclosed here feature a networkhub connected to a bus of a first network and connected to a secondnetwork in an onboard network system. The onboard network systemincludes the first network for transmission of first-type framesrelating to traveling control of a vehicle over the bus following afirst communication protocol, and the second network for transmission ofsecond-type frames following a second communication protocol that isdifferent from the first communication protocol. The network hubincludes: a first reception buffer; a second reception buffer; a firsttransmission buffer; a second transmission buffer; a first receiver thatsequentially receives the first-type frames from the bus and stores datawithin the first-type frames in the first reception buffer; a secondreceiver that sequentially receives the second-type frames from thesecond network and stores data within the second-type frames in thesecond reception buffer; a processor that selects which of the firstnetwork and the second network is a destination for data that is acontent of one of the first reception buffer and the second receptionbuffer, stores the data in the first transmission buffer in a case ofselecting the first network, and stores the data in the secondtransmission buffer in a case of selecting the second network; and atransmitter that transmits first yet-to-be-transmitted data in the firsttransmission buffer and second yet-to-be-transmitted data in the secondtransmission buffer.

The transmitter performs priority transmission control, where priorityyet-to-be-transmitted data in a priority transmission buffer that is oneof the first transmission buffer and the second transmission buffer istransmitted with priority over non-priority yet-to-be-transmitted datain a non-priority transmission buffer that is another of the firsttransmission buffer and the second transmission buffer.

According to the present disclosure, further improvement can berealized.

It should be noted that general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, a storage medium, or any selective combination thereof.

Additional benefits and advantages of the disclosed embodiments willbecome apparent from the specification and drawings. The benefits and/oradvantages may be individually obtained by the various embodiments andfeatures of the specification and drawings, which need not all beprovided in order to obtain one or more of such benefits and/oradvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating an onboard network including twonetworks in an onboard network system according to a first embodiment;

FIG. 2 is a diagram illustrating a schematic configuration of theonboard network system according to the first embodiment;

FIGS. 3A and 3B are diagrams illustrating a format of a data framestipulated in the CAN protocol (also referred to as “CAN frame”);

FIG. 4 is a diagram illustrating the format of an Ethernet (registeredtrademark) frame (also referred to as “E-frame”) exchanged over part ofthe onboard network;

FIG. 5 is a configuration diagram of an electronic control unitconnected to two networks according to the first embodiment (alsoreferred to as “X-ECU”);

FIG. 6 is a diagram illustrating an example of a reception ID list usedat the electronic control unit (X-ECU) network hub, and so forth, in thefirst embodiment;

FIG. 7 is a configuration diagram of the hub according to the firstembodiment;

FIG. 8 is a diagram illustrating an example of transfer rule informationused at the hub according to the first embodiment;

FIG. 9 is a flowchart illustrating an example of data processing by theX-ECU according to the first embodiment;

FIG. 10 is a flowchart illustrating an example of reception data readoutprocessing by the X-ECU according to the first embodiment;

FIG. 11 is a flowchart illustrating an example of transmission datagenerating processing by the X-ECU according to the first embodiment;

FIG. 12 is a flowchart illustrating an example of data transmissionprocessing by the X-ECU according to the first embodiment (continuing toFIG. 13);

FIG. 13 is a flowchart illustrating an example of data transmissionprocessing by the X-ECU according to the first embodiment (continuingfrom FIG. 12);

FIG. 14 is a flowchart illustrating an example of data transferprocessing by the hub according to the first embodiment;

FIG. 15 is a flowchart illustrating an example of transfer datagenerating processing by the hub according to the first embodiment;

FIG. 16 is a sequence diagram illustrating an example of a processingsequence by ADAS functions of the X-ECU according to the firstembodiment;

FIG. 17 is a diagram illustrating an example of a communication sequencerelating to transfer functions of the hub according to the firstembodiment;

FIG. 18 is a flowchart illustrating an example of reception data readoutprocessing according to a modification of the first embodiment;

FIG. 19 is a flowchart illustrating an example of data transmissionprocessing according to a modification of the first embodiment;

FIG. 20 is a diagram illustrating a schematic configuration of theonboard network system according to a second embodiment;

FIG. 21 is a diagram illustrating an example of degree-of-prioritycontrol information, used by a hub according to the second embodiment;

FIG. 22 is a diagram illustrating an example of a communication sequencerelated to transfer functions of the hub according to the secondembodiment;

FIG. 23 is a diagram illustrating a schematic configuration of anonboard network system according to a first modification;

FIG. 24 is a diagram illustrating a schematic configuration of anonboard network system according to a second modification;

FIG. 25 is a diagram illustrating a schematic configuration of anonboard network system according to a third modification;

FIG. 26 is a diagram illustrating a schematic configuration of anonboard network system according to a fourth modification;

FIG. 27 is a diagram illustrating a schematic configuration of anonboard network system according to a fifth modification; and

FIG. 28 is a diagram illustrating a schematic configuration of anonboard network system according to a sixth modification.

DETAILED DESCRIPTION

Underlying Knowledge Forming Basis of the Present Disclosure

In recent years, a great number of devices called electronic controlunits (ECU) have been placed in systems in automobiles. A networkconnecting these ECUs is referred to as an onboard network. Manystandards exist for onboard networks. One of the most mainstream ofthese onboard networks is a standard called Controller Area Network(CAN), that is stipulated in ISO11898-1. In CAN, ECUs (nodes) connectedto a bus that is a wired transmission path exchange frames (messages).There are no identifiers indicating transmission destinations ortransmission sources in CAN. A transmitting node appends an ID (CAN-ID)to each frame and transmits (i.e., sends signals out onto the bus), andthe receiving nodes receive (i.e., read signals from the bus) only ofmessages of CAN-IDs set beforehand. In CAN, a CAN-ID relates to thedegree of priority of the message, and in a case where multiple nodestransmit messages at the same time, communication arbitration isperformed in accordance with the values of the CAN-IDs. Communicationarbitration and the like enables situations where messages collide andare lost on the bus to be avoided, so a CAN network is suitable fortransmitting data regarding traveling control of vehicles and so forth,where loss of data could prevent safe traveling of the vehicle.

There also are known advanced driver-assistance systems (ADAS).Functions of ADAS (e.g., parking assistance, lane-keeping assistance,collision avoidance functions, and so forth) use information obtained bysensors connected to the onboard network system for example, which is tosay that images taken by onboard cameras and information obtained byLight Detection and Ranging (LIDAR) is used, the surrounding environmentof the vehicle is recognized by ECUs based on the information, and thevehicle is controlled in accordance with the results of recognition.Increasingly sophisticated ADASs can lead to increase in the amount ofinformation communicated over the onboard network (data amount). Theamount of data that can be transmitted by one frame (data frame instandard format) is eight bytes or less in CAN, which is not suitablefor transmission of relatively large data amounts, such as images takenby onboard cameras, and so forth.

There is a standard called Ethernet (registered trademark) stipulated byIEEE 802.3, as a standard to transmit a greater amount of information. Aframe in Ethernet (registered trademark) includes information indicatinga transmission destination and a transmission source, in the header. Themaximum amount of data that can be transmitted by one frame is greaterin Ethernet (registered trademark) as compared to CAN, and thecommunication speed is faster. As described above, a CAN network thatcan avoid loss of messages is more suitable for data transmission forvehicle traveling control, but some loss of data such as images taken byonboard cameras or the like has little adverse effect. Accordingly,Ethernet (registered trademark) is more suitable for transmission ofrelatively large data such as images taken by onboard cameras or thelike, as compared to a CAN network.

Japanese Unexamined Patent Application Publication No. 2016-111477describes a gateway that relays messages between devices conforming tothe CAN protocol and devices conforming to the Ethernet (registeredtrademark) protocol and so forth. However, Japanese Unexamined PatentApplication Publication No. 2016-111477 does not indicate specificcontent of processing of the gateway relaying (transferring) messagesbetween electronic control units connected to a CAN bus (hereinafteralso referred to as “C-ECU”) and electronic control units having anEthernet (registered trademark) interface (hereafter referred to as“E-ECU”).

The present Inventors have conceived the embodiments of the presentdisclosure based on the above-described consideration.

A network hub according to an aspect of the present disclosure is anetwork hub connected to a bus of a first network and connected to asecond network in an onboard network system. The onboard network systemincludes the first network for transmission of first-type framesrelating to traveling control of a vehicle over the bus following afirst communication protocol, and the second network for transmission ofsecond-type frames following a second communication protocol that isdifferent from the first communication protocol. The network hubincludes: a first reception buffer; a second reception buffer; a firsttransmission buffer; a second transmission buffer; a first receiver thatsequentially receives the first-type frames from the bus and stores datawithin the first-type frames in the first reception buffer; a secondreceiver that sequentially receives the second-type frames from thesecond network and stores data within the second-type frames in thesecond reception buffer; a processor that selects which of the firstnetwork and the second network is a destination for data that is acontent of one of the first reception buffer and the second receptionbuffer, stores the data in the first transmission buffer in a case ofselecting the first network, and stores the data in the secondtransmission buffer in a case of selecting the second network; and atransmitter that transmits first yet-to-be-transmitted data in the firsttransmission buffer and second yet-to-be-transmitted data in the secondtransmission buffer. The transmitter performs priority transmissioncontrol, where priority yet-to-be-transmitted data in a prioritytransmission buffer that is one of the first transmission buffer and thesecond transmission buffer is transmitted with priority overnon-priority yet-to-be-transmitted data in a non-priority transmissionbuffer that is another of the first transmission buffer and the secondtransmission buffer. Now, a network hub is a communication device (e.g.,a relay device) connected to bus of a first network and to a secondnetwork, that includes data in a frame following a communicationprotocol used at a network that is the transmission destination of thedata, and transmits the frame as signals corresponding the network thatis the transmission destination. Such network hubs include gateways andso forth, for example. Using this network hub to relay (transfer)contents (data) of frames among networks enables one of a flow of databeing received from a first network and transmitted to a second network,and a flow of data being received from the second network andtransmitted to the first network, to be prioritized (i.e., transmissionof data of that one can be performed first). Thus, according to thisnetwork hub, transmission of data can be appropriately performed bypriority transmission control if a priority transmission buffer wheredata of which the destination is the one network is stored is decidedappropriately, taking into consideration the properties of each of thefirst network and second network.

An arrangement may be made where the priority transmission buffer is thefirst transmission buffer, the transmitter performs transmission of thefirst yet-to-be-transmitted data in the first transmission buffer bysending a first-type frame including the first yet-to-be-transmitteddata to the bus of the first network in a case where predeterminedexception conditions are not satisfied, and by sending a second-typeframe including the first yet-to-be-transmitted data to the secondnetwork in a case where the predetermined exception conditions aresatisfied, and the transmitter performs transmission of the secondyet-to-be-transmitted data in the second transmission buffer by sendinga second-type frame including the second yet-to-be-transmitted data tothe second network. The predetermined exception conditions may besatisfied when an abnormality is detected in a part of the firstnetwork. According to these, in a case where there is a possibility thatappropriate transmission may not be performed if data is transmitted tothe first network, data is transmitted using the second network as a asa diversion route. The data in the first transmission buffer of whichthe destination is the first network can be transmitted by this networkhub over the second network that is a diversion route, and thereafter betransported again from the second network to the destination firstnetwork by another network hub or the like. Even in a case where thedata in the first transmission buffer and the data in the secondtransmission buffer compete on the second network, each data istransmitted by an appropriate order, by priority transmission controlwhere the first transmission buffer is given priority. That is to say,priority is given to the data relating to traveling control of thevehicle, thereby preventing transmission of other data (e.g., large-sizedata such as images or the like) from adversely affecting safe travelingof the vehicle and so forth. Even in a case where the configurationrealizing transmission of the data in the first transmission buffer(e.g., communication circuit, processor, etc.) and the configurationrealizing transmission of the second transmission buffer are partiallyused in common in the network hub, transmission of data relating totraveling control of the vehicle is given priority, thereby preventingtransmission of other data from adversely affecting safe traveling ofthe vehicle and so forth.

An arrangement may be made where the transmitter performs the prioritytransmission control by repeatedly confirming the first transmissionbuffer and the second transmission buffer, transmitting the priorityyet-to-be-transmitted data in the priority transmission buffer in a casewhere the first yet-to-be-transmitted data is in the first transmissionbuffer and the second yet-to-be-transmitted data is in the secondtransmission buffer during the confirming, transmitting the firstyet-to-be-transmitted data in the first transmission buffer in a casewhere the first yet-to-be-transmitted data is in the first transmissionbuffer and the second yet-to-be-transmitted data is not in the secondtransmission buffer during the confirming, and transmitting the secondyet-to-be-transmitted data in the second transmission buffer in a casewhere the first yet-to-be-transmitted data is not in the firsttransmission buffer and the second yet-to-be-transmitted data is in thesecond transmission buffer during the confirming. Accordingly, in a casewhere there is data to be transmitted of which the first network is thedestination, and data to be transmitted of which the second network isthe destination, the one data corresponding to the priority transmissionbuffer that has been decided beforehand is transmitted first, so the onedata can be speedily transmitted.

An arrangement may be made where the transmitter performs the prioritytransmission control by repeatedly confirming the first transmissionbuffer and the second transmission buffer, transmitting a predeterminedquantity of the priority yet-to-be-transmitted data in the prioritytransmission buffer, and thereafter transmitting one of the non-priorityyet-to-be-transmitted data in the non-priority transmission buffer, in acase where the first yet-to-be-transmitted data is in the firsttransmission buffer and the second yet-to-be-transmitted data is in thesecond transmission buffer during the confirming, transmitting the firstyet-to-be-transmitted data in the first transmission buffer in a casewhere the first yet-to-be-transmitted data is in the first transmissionbuffer and the second yet-to-be-transmitted data is not in the secondtransmission buffer during the confirming, and transmitting the secondyet-to-be-transmitted data in the second transmission buffer in a casewhere the first yet-to-be-transmitted data is not in the firsttransmission buffer and the second yet-to-be-transmitted data is in thesecond transmission buffer during the confirming. The predeterminedquantity may be decided to be, for example, a quantity greater than oneworth of the data in the priority transmission buffer (e.g., a count oftwo or more data, a data amount that is twice or more that of one dataworth, or the like), so that the data within the priority transmissionbuffer is transmitted with priority. Accordingly, a situation where nodata in the non-priority transmission buffer is transmitted at all dueto consecutive transmission of data in the priority transmission buffercan be prevented, for example.

An arrangement may be made where the transmitter performs the prioritytransmission control by repeatedly confirming the first transmissionbuffer and the second transmission buffer, transmitting the priorityyet-to-be-transmitted data in the priority transmission buffer when anon-transmission time of the non-priority yet-to-be-transmitted data inthe non-priority transmission buffer does not exceed a predeterminedthreshold value, and transmitting the non-priority yet-to-be-transmitteddata in the non-priority transmission buffer when the non-transmissiontime exceeds the predetermined threshold value, transmitting the firstyet-to-be-transmitted data in the first transmission buffer in a casewhere the first yet-to-be-transmitted data is in the first transmissionbuffer and the second yet-to-be-transmitted data is not in the secondtransmission buffer during the confirming, and transmitting the secondyet-to-be-transmitted data in the second transmission buffer in a casewhere the first yet-to-be-transmitted data is not in the firsttransmission buffer and the second yet-to-be-transmitted data is in thesecond transmission buffer during the confirming. The predeterminedthreshold value relating to non-transmission time may be decided to be,for example, a time longer than the time required for transmission ofone worth of data in the priority transmission buffer, so that the datawithin the priority transmission buffer is transmitted with priority.Accordingly, a situation where no data in the non-priority transmissionbuffer is transmitted at all due to consecutive transmission of data inthe priority transmission buffer can be prevented, for example.

An arrangement may be made where the processor performs priority readoutcontrol for selecting which of the first network and the second networkis the destination, where content of a priority reception buffer that isone of the first reception buffer and the second reception buffer isread with priority over content of a non-priority reception buffer thatis another of the first transmission buffer and the second transmissionbuffer, and in a case where the priority transmission buffer is thefirst transmission buffer, the priority reception buffer is the firstreception buffer, and in a case where the priority transmission bufferis the second transmission buffer, the priority reception buffer is thesecond reception buffer. Accordingly, in a case where the configurationrealizing readout of the data in the first reception buffer andselecting a destination of the data (e.g., processor, etc.) and theconfiguration realizing readout of the data in the second receptionbuffer and selecting a destination of the data are partially used incommon in the network hub, data in one reception buffer can be givenpropriety in accordance with the network that will realize speedytransmission.

An arrangement may be made where the processor performs the priorityreadout control by repeatedly confirming the first reception buffer andthe second reception buffer, reading priority unread data in thepriority reception buffer out of the first reception buffer and thesecond reception buffer in a case where first unread data is in thefirst reception buffer and second unread data is in the second receptionbuffer during the confirming, reading the first unread data in the firstreception buffer in a case where the first unread data is in the firstreception buffer and the second unread data is not in the secondreception buffer during the confirming, and reading the second unreaddata in the second reception buffer in a case where the first unreaddata is not in the first reception buffer and the second unread data isin the second reception buffer during the confirming. Accordingly, in acase where there is unread data received from the first network (i.e.,data that has not been read out) and unread data received from thesecond network the one data corresponding to the priority receptionbuffer decided beforehand is read out first, so that one data can bespeedily transmitted.

An arrangement may be made where the processor performs the priorityreadout control by repeatedly confirming the first reception buffer andthe second reception buffer, reading a predetermined quantity ofpriority unread data in the priority reception buffer out of the firstreception buffer and the second reception buffer, and thereafter readingone non-priority unread data in the non-priority reception buffer, in acase where first unread data is in the first reception buffer and secondunread data is in the second reception buffer during the confirming,reading the first unread data in the first reception buffer in a casewhere the first unread data is in the first reception buffer and thesecond unread data is not in the second reception buffer during theconfirming, and reading the second unread data in the second receptionbuffer in a case where the first unread data is not in the firstreception buffer and the second unread data is in the second receptionbuffer during the confirming. The predetermined quantity may be decidedto be, for example, a quantity greater than one worth of the data in thepriority reception buffer (e.g., a count of two or more data, a dataamount that is twice or more that of one data worth, or the like), sothat the data within the priority reception buffer is read out withpriority. Accordingly, a situation where no data in the non-priorityreception buffer is read out at all and not transmitted due toconsecutive readout of data in the priority reception buffer can beprevented, for example.

An arrangement may be made where the processor performs the priorityreadout control by repeatedly confirming the first reception buffer andthe second reception buffer, reading priority unread data in thepriority reception buffer when a non-readout time of non-priority unreaddata in the non-priority reception buffer does not exceed apredetermined threshold value, and reading the non-priority unread datain the non-priority reception buffer when the non-readout time exceedsthe predetermined threshold value, in a case where first unread data isin the first reception buffer and second unread data is in the secondreception buffer during the confirming, reading the first unread data inthe first reception buffer in a case where the first unread data is inthe first reception buffer and the second unread data is not in thesecond reception buffer during the confirming, and reading the secondunread data in the second reception buffer in a case where the firstunread data is not in the first reception buffer and the second unreaddata is in the second reception buffer during the confirming. Thepredetermined threshold value relating to non-readout time (i.e., timenot read out yet) may be decided to be, for example, a time longer thanthe time required for readout of one worth of data in the priorityreception buffer, so that the data within the priority reception bufferis read out with priority. Accordingly, a situation where no data in thenon-priority reception buffer is read out at all and not transmitted dueto consecutive readout of data in the priority reception buffer can beprevented, for example.

In a case where the processor selects the first network as thedestination for the data that is the content of the second receptionbuffer, the data may be split into a plurality of data, and theplurality of data may be stored in the first transmission buffer.Accordingly, even in a case where data exceeding the maximum data amount(maximum data length) of a first-type frame transmitted over the firstnetwork is received from the second network, transfer can beappropriately performed by splitting.

An arrangement may be made where the first communication protocol is theCAN (Controller Area Network) protocol, the second communicationprotocol is the Ethernet (registered trademark) protocol, the first-typeframes are data frames, and the second-type frames are Ethernet(registered trademark) frames. Accordingly, appropriate data transfercan be performed between a CAN network suitable for transmission of datarelating to traveling control of the vehicle, and an Ethernet(registered trademark) network suitable for transmission of large-sizedata such as images and so forth.

A maximum data amount of the second-type frames following the secondcommunication protocol may be greater than a maximum data amount of thefirst-type frames following the first communication protocol.Accordingly, appropriate data transfer can be performed between thefirst network serving as a control system network suitable fortransmission of data relating to traveling control of the vehicle, andthe second network serving as an information system network suitable fortransmission of large-size data such as images and so forth.

The priority transmission buffer may be the first transmission bufferwhile the vehicle is traveling, and may be the second transmissionbuffer while the vehicle is stopped. Accordingly, when the vehicle istraveling, transmission of data relating to traveling control of thevehicle can be speedily performed, and when the vehicle is stopped,transmission of data other than data relating to traveling control ofthe vehicle (e.g., multimedia data such as images, audio, etc., and soforth) can be speedily performed, for example.

A transfer method according to an aspect of the present disclosure is atransfer method for a network hub connected to a bus of a first networkand connected to a second network in an onboard network system. Theonboard network system includes the first network for transmission offirst-type frames relating to traveling control of a vehicle over thebus following a first communication protocol, and the second network fortransmission of second-type frames following a second communicationprotocol that is different from the first communication protocol. Thenetwork hub includes a first reception buffer, a second receptionbuffer, a first transmission buffer, and a second transmission buffer.The transfer method includes: sequentially receiving the first-typeframes from the bus and storing data within the first-type frames in thefirst reception buffer; sequentially receiving the second-type framesfrom the second network and storing data within the second-type framesin the second reception buffer; selecting which of the first network andthe second network is a destination for data that is a content of one ofthe first reception buffer and the second reception buffer, storing thedata in the first transmission buffer in a case of selecting the firstnetwork, and storing the data in the second transmission buffer in acase of selecting the second network; and transmitting firstyet-to-be-transmitted data in the first transmission buffer and secondyet-to-be-transmitted data in the second transmission buffer. In thetransmitting, priority transmission control is performed, where priorityyet-to-be-transmitted data in a priority transmission buffer that is oneof the first transmission buffer and the second transmission buffer istransmitted with priority over non-priority yet-to-be-transmitted datain a non-priority transmission buffer that is another of the firsttransmission buffer and the second transmission buffer. Accordingly,transmission of data can be appropriately performed by prioritytransmission control if a priority transmission buffer where data ofwhich the destination is the one network is stored is decidedappropriately, taking into consideration the properties of each of thefirst network and second network.

An onboard network system according to an aspect of the presentdisclosure is an onboard network system including: a first network fortransmission of first-type frames relating to traveling control of avehicle over a bus following a first communication protocol; a secondnetwork for transmission of second-type frames following a secondcommunication protocol that is different from the first communicationprotocol; an electronic control unit connected to the bus; an electroniccontrol unit connected to the second network; and a network hubconnected to the bus and the second network. The network hub includes afirst reception buffer, a second reception buffer, a first transmissionbuffer, a second transmission buffer, a first receiver that sequentiallyreceives the first-type frames from the bus and stores data within thefirst-type frames in the first reception buffer, a second receiver thatsequentially receives the second-type frames from the second network andstores data within the second-type frames in the second receptionbuffer, a processor that selects which of the first network and thesecond network is a destination for data that is a content of one of thefirst reception buffer and the second reception buffer, stores the datain the first transmission buffer in a case of selecting the firstnetwork, and stores the data in the second transmission buffer in a caseof selecting the second network, and a transmitter that transmits firstyet-to-be-transmitted data in the first transmission buffer and secondyet-to-be-transmitted data in the second transmission buffer. Thetransmitter performs priority transmission control, where priorityyet-to-be-transmitted data in a priority transmission buffer that is oneof the first transmission buffer and the second transmission buffer istransmitted with priority over non-priority yet-to-be-transmitted datain a non-priority transmission buffer that is another of the firsttransmission buffer and the second transmission buffer. Accordingly,transmission of data can be appropriately performed between electroniccontrol units connected to networks that are different from each other.

It should be noted that these general or specific embodiments may beimplemented as a system, a method, an integrated circuit, a computerprogram, or a computer-readable recording medium such as a CD-ROM, andmay be realized by any combination of a system, method, integratedcircuit, computer program, and recording medium.

The following is a description of an onboard network system including anelectronic control unit (ECU) and a network hub according to embodimentswith reference to the drawings. Note that the embodiments describedbelow are all specific examples of the present disclosure. Accordingly,values, components, placements and connected states of components, steps(processes) and the order of steps, and so forth illustrated in thefollowing embodiments, are only exemplary, and do not restrict thepresent disclosure. Components in the following embodiments which arenot included in an independent Claim are optionally addable components.The drawings are schematic diagrams, and are not necessarily created inan exact manner.

First Embodiment

An onboard network system 10 including multiple ECUs and a network hubthat exchange data over an onboard network will be described as anembodiment of the present disclosure with reference to the drawings.

1.1 Overall Configuration of Onboard Network System 10

FIG. 1 is a diagram illustrating an onboard network 11 including twonetworks in the onboard network system 10. Installed in a vehicle 9 arevarious types of devices, such as control devices, sensors, actuators,user interface devices, ECUs, and so forth. The onboard network system10 is a network communication system that has the onboard network 11 forthe various devices such as the sensors, ECUs, and so forth, installedin the vehicle 9, to exchange information in cooperation. The onboardnetwork 11 is configured including a control system network 1 (firstnetwork) where various types of frames such as data frames relating totraveling control of the vehicle 9 are transmitted over a bus (CAN bus)following the CAN protocol, and an information system network 2 (secondnetwork) where Ethernet (registered trademark) frames (E-frames) aretransmitted following the Ethernet (registered trademark) protocol. Theonboard network 11 can be wirelessly connected to an external network 91outside of the vehicle 9, such as the Internet or the like.

The maximum data amount of an E-frame (1500 bytes or more) stipulated bythe Ethernet (registered trademark) protocol is considerably greaterthan the maximum data amount of CAN frame (eight byes for standardformat) stipulated by the CAN protocol. electronic control unitsrelating to traveling control of the vehicle 9 (C-ECUs) and so forth areconnected to the bus of the control system network 1. Relatively smalldata, such as vehicle state data indicating the state of the vehicle 9that is the base for traveling control of the vehicle 9, vehicle controldata for traveling control that indicates operation instructions ofactuators installed in the vehicle 9, and so forth, are primarilytransmitted over the control system network 1. Various types of sensorsthat observe the situation around the vehicle 9, such as onboard cameras(i.e., image sensors), LIDAR, and so forth, are connected to theinformation system network 2. Electronic control units for processinginformation from the sensors and providing information to the passenger(user) of the vehicle 9 (E-ECUs) may also be connected to theinformation system network 2. Sensor information such as images taken byonboard cameras, three-dimensional data generated by LIDAR, and so forth(e.g., relatively large data generated by sensors) is primarilytransmitted over the information system network 2.

FIG. 2 illustrates the overall configuration of the onboard networksystem 10. The onboard network system 10 includes the control systemnetwork 1, the information system network 2, a network hub 200 connectedto both networks, and an electronic control unit 100 connected to bothnetworks (referred to as “X-ECU”).

C-ECUs 500 a through 500 c, which are ECUs having communicationinterfaces conforming to the CAN protocol, are connected to a bus 30 athat is a transmission path in the control system network 1. The C-ECUs500 a through 500 c respectively are an engine control ECU that handlescontrol of the engine, a steering control ECU that handles control ofsteering, and a brake control ECU that handles control of braking, andso forth. The C-ECUs 500 a through 500 c communicate with each other viathe bus 30 a, and exchange frames following the CAN protocol. The C-ECUs500 a through 500 c respectively obtain the state of the engine,steering, brakes, and so forth, and transmit data frames (CAN frames)indicating state to the bus 30 a making up the control system network 1,periodically for example. The C-ECUs 500 a through 500 c can alsoreceive CAN frames from the bus 30 a making up the control systemnetwork 1, interpret the CAN frames, distinguish whether or not the CANframes are CAN frames having CAN-IDs that should be received, and effectcontrol relating to the engine, steering, brakes, and so forth,connected to the C-ECUs, in accordance with data within the CAN frames(contents of data fields) as necessary, and also generate and transmitCAN frames as necessary.

In the information system network 2, an E-ECU 300 a that is an ECUhaving a communication interface conforming to the Ethernet (registeredtrademark) protocol, a camera 300 b, a LIDAR 300 c, and a GlobalPositioning System (GPS) receiver (referred to as “GPS”) 300 d, areconnected by an E-hub 400 that is a network hub conforming to Ethernet(registered trademark), and each of Ethernet (registered trademark)cables 20 a through 20 d that are transmission paths. The E-ECU 300 aperforms transmission and receptions of E-frames following the Ethernet(registered trademark) protocol. The E-ECU 300 a may have a display, forexample, and be an ECU having functions of providing information to theuser. The E-ECU 300 a, camera 300 b, LIDAR 300 c, and GPS 300 d, eachhave unique Media Access Control (MAC) addresses. The E-hub 400 is, forexample, an Ethernet (registered trademark) switch (switching hub). TheE-hub 400 stores a MAC address table for example, and learnscorresponding MAC addresses for each cable connecting terminal (port)upon receiving E-frames. The E-hub 400 also selects a port to serve as atransfer destination based on a destination MAC address in the header ofa received E-frame in accordance with the MAC address table, and sendsthe E-frame out to the cable connected to that port, therebytransferring the E-frame.

The X-ECU 100 is an ECU that has a communication interface conforming tothe CAN protocol and a communication interface conforming to theEthernet (registered trademark) protocol, and handles some types of ADASfunctions (e.g., parking assistance, lane-keeping assistance, collisionavoidance functions, and so forth). The X-ECU 100 is connected to thebus 30 a, and is connected to the E-hub 400 by an Ethernet (registeredtrademark) cable 20 e. The X-ECU 100 has a unique MAC address.

The hub 200 is a communication device that has a communication protocolconversion function, and has a communication data relay function. Thehub 200 is connected to the bus 30 a, and is connected to the E-hub 400by an Ethernet (registered trademark) cable 20 f. The hub 200 has aunique MAC address, for example. The hub 200 is also connected to anexternal communication device 92. The external communication device 92is a device having communication functions of communicating with aserver device outside of the vehicle 9 (e.g., a computer havingfunctions of providing information to the vehicle or the like) via theexternal network 91 and so forth, for example.

Note that many more ECUs may be included in the onboard network system10 bedsides the X-ECU 100, E-ECU 300 a, and C-ECUs 500 a through 500 c.For example, C-ECUs that are omitted from illustration may be connectedto the bus 30 a besides the C-ECUs 500 a through 500 c. Also, E-ECUsomitted from illustration may be connected to the E-hub 400, eitherdirectly or via another E-hub, for example.

The ECUs (E-ECUs, C-ECUs, and X-ECU) are devices that include, forexample, processors (microprocessors), digital circuits such as memoryand so forth, analog circuits, communication circuits, and so forth. Thememory is ROM, RAM, and so forth, and can store programs (computerprograms serving as software) that are executed by processors. Thememory may include non-volatile memory. An ECU realized various types offunctions by a processor operating in accordance with programs (computerprograms), for example. Note that a computer program is configured bycombining multiple sets of command codes instructing commands withrespect to the processor, to achieve predetermined functions.

1.2 Configuration of Frames Exchanged Over Onboard Network 11

The C-ECUs 500 a through 500 c and so forth exchange frames followingthe CAN protocol on the control system network 1. Frames in the CANprotocol include data frames, remote frames, overload frames, and errorframes. Data frames will be described with primary focus here.

FIGS. 3A and 3B illustrate the format of a data frame (CAN frame)exchange exchanged over the control system network 1. FIG. 3Aillustrates a standard format. A data frame includes a start of frame(SOF), ID (CAN-ID), remote transmission request (RTR), identifierextension (IDE), reserved bit “r”, size data, cyclic redundancy check(CRC) sequence, CRC delimiter “DEL”, acknowledgement (ACK) slot, ACKdelimiter “DEL”, and end of frame (EOF), in the standard format. The ID(CAN-ID) serving as the content of the ID field is an identifierindicating the type of data, and also is referred to as a message ID.Note that in CAN, in a case where multiple nodes start transmission atthe same time, communication arbitration is performed, where a framehaving the smallest CAN-ID value is given priority. Size is a datalength code (DLC) indicating the length of the following data field(data). The specification of the data (content of the data) is notstipulated in the CAN protocol, and is set in the onboard network system10. Accordingly, the specification can be dependent on the model of thevehicle, the manufacturer (automaker), or the like. FIG. 3B illustratesan extended format. Although the standard format will be described asbeing used on the control system network 1 in the present embodiment, ina case of using the extended format on the control system network 1, the29 bits of the 11-bit base ID in the ID field (part of the CAN-ID), andthe 18-bit extended ID (remainder of CAN-ID), having been combined, canbe used as the CAN-ID.

FIG. 4 illustrates the format of frames exchanged on the informationsystem network 2 (E-frames). An E-frame is confirmed by adding a header(Ethernet (registered trademark) header) in front of the payload thatstores data, which is the primary content being transmitted, asillustrated in FIG. 4. The header includes destination MAC address,transmission source MAC address, and type.

1.3 Configuration of X-ECU 100

FIG. 5 is a configuration diagram of the X-ECU 100. The X-ECU 100 isconfigured including a reception unit 110 a (first reception unit), areception unit 110 b (second reception unit), a reception buffer 120 a(first reception buffer), a reception buffer 120 b (second receptionbuffer), a generating unit 130, a transmission buffer 140 a (firsttransmission buffer), a transmission buffer 140 b (second transmissionbuffer), a transmission unit 150, and a degree-of-priority setting unit160. These components are realized by communication circuits in theX-ECU 100, a processor or digital circuits executing programs stored inthe memory, and so forth.

The reception buffer 120 a, reception buffer 120 b, transmission buffer140 a, and transmission buffer 140 b are each configured of storagemedia such as memory or the like, and are first-in first-out (FIFO)buffers, for example. The reception buffer 120 a (first receptionbuffer) is also referred to as a control system data reception buffer,and the transmission buffer 140 a (first transmission buffer) is alsoreferred to as a control system data transmission buffer. The receptionbuffer 120 b (second reception buffer) is also referred to as aninformation system data reception buffer, and the transmission buffer140 b (second transmission buffer) is also referred to as an informationsystem data transmission buffer.

The reception unit 110 a sequentially receives CAN frames from the bus30 a of the control system network 1. Each time a CAN frame is received,the reception unit 110 a confirms whether the CAN-ID of the received CANframe is an ID that should be received, based on a reception ID list,and if an ID that should be received, stores the contents of the CANframe in the reception buffer 120 a. The contents of a CAN frame thatthe reception unit 110 a stores in the reception buffer 120 a isinformation where the CAN-ID and size (DLC) and so forth have been addedto data (the contents of the data field). FIG. 6 illustrates an exampleof a reception ID list that the X-ECU 100 uses. The reception ID list ofthe X-ECU 100 lists CAN-IDs of CAN frames including vehicle state dataand so forth, for example. If the CAN-ID of a received CAN frame is anID not shown in the reception ID list, the reception unit 110 a cancelsreception of that CAN frame, and does not store the contents of that CANframe in the reception buffer 120 a.

The reception unit 110 b sequentially receives E-frames including theMAC address of the X-ECU 100 or the like as the destination MAC addressfor example, from the cable 20 e of the information system network 2.Each time an E-frame is received, the reception unit 110 b stores thecontents of that E-frame in the reception buffer 120 b. The contents ofan E-frame that the reception unit 110 a stores in the reception buffer120 b is data (contents of the payload), for example. For example,E-frames that have images and other data from various types of sensorssuch as the camera 300 b, LIDAR 300 c, GPS 300 d, and so forth, in thepayloads thereof, are transmitted with the X-ECU 100 as the destination,and the reception unit 110 b receives these E-frames.

The generating unit 130 sequentially generates control system data(first-type data) that is data for traveling control of the vehicle 9and information system data (second-type data) that is data used forother than traveling control of the vehicle 9 from the contents of thereception buffer 120 a and reception buffer 120 b, stores the generatedcontrol system data in the transmission buffer 140 a (control systemdata transmission buffer) and stores the generated information systemdata in the transmission buffer 140 b (information system datatransmission buffer). The generating unit 130 is configured including adetecting unit 131, a control judging unit 132, and a data generatingunit 133.

The detecting unit 131 detects the situation in the environment aroundthe vehicle 9 and various types of items set beforehand regarding thestate of the vehicle 9 (e.g., distance to an obstruction in the path oftravel of the vehicle 9, relative speed as to the obstruction, anglebetween white, yellow, and other color lines displayed on the pavementand the direction of travel of the vehicle 9, and so forth), based onthe data read out from the control system data reception buffer orinformation system data reception buffer. In a case of reading out datafrom each of the control system data reception buffer and informationsystem data reception buffer, the detecting unit 131 performs priorityreadout control, where the contents of a priority reception buffer thatis one of the control system data reception buffer and informationsystem data reception buffer are read out with higher propriety than thecontents of a non-priority buffer that is the other buffer, based onpriority information set in the degree-of-priority setting unit 160(e.g., information for identifying the priority reception buffer fromwhich readout should be performed with priority, or the like). Thedegree-of-priority setting unit 160 stores priority information in aregion of a storage medium such as memory. Note that in one example ofthe present embodiment, priority information is set at thedegree-of-priority setting unit 160 indicating that data of the controlsystem data reception buffer should be read out with priority over theinformation system data reception buffer. In a case where data has beenread out from the reception buffers 120 a and 120 b, that data isdeleted from the reception buffer, for example.

The control judging unit 132 judges whether or not traveling control ofthe vehicle 9 is necessary, or whether or not control of the varioustypes of sensors installed in the vehicle 9 is necessary, based on theresults of detection by the detecting unit 131, and in a case wherecontrol is necessary, sets the content of control based on apredetermined algorithm set beforehand, and notifies the data generatingunit 133. For example, in a case where distance to an obstruction in thepath of the vehicle 9, vehicle speed, and so forth satisfy certainconditions, control content to bring the vehicle 9 to an emergency stopmay be obtained. Also, for example, in a case where sensor informationobtained from a sensor satisfies certain conditions, control content foradjusting the sensor may be obtained.

The data generating unit 133 generates control system data such asvehicle control data or the like in accordance with the control contentnotified thereto in a case where the control judging unit 132 has judgedthat traveling control of the vehicle 9 is necessary, and stores thatcontrol system data in the control system data transmission buffer. Notethat the data generating unit 133 sets a CAN-ID in accordance with thecontrol content notified thereto, attaches the CAN-ID to that vehiclecontrol data or the like, and stores in the control system datatransmission buffer. The data generating unit 133 generates informationsystem data such as sensor control data or the like in accordance withthe contents of control notified thereto in a case where the controljudging unit 132 has judged that sensor control is necessary, and storesthat information system data in the information system data transmissionbuffer.

Also, the data generating unit 133 sets a MAC address serving as adestination of sensor control data or the like in accordance with thecontrol content notified thereto, attaches the MAC address to thatsensor control data or the like, and stores in the information systemdata transmission buffer. The data generating unit 133 generates controlsystem data by processing based on data relating to a CAN frame read outfrom the control system data reception buffer at the least (e.g.,vehicle state data or the like), and generates information system databy processing based on data relating to an E-frame read out from theinformation system data reception buffer at the least (e.g., sensorinformation such as images or the like). Note that the data generatingunit 133 may generate control system data or information system data byprocessing based on both vehicle state data and sensor information, forexample.

The transmission unit 150 is configured including a frame constructingunit 151 that constructs frames in accordance with the communicationprotocols corresponding to each of the control system network 1 andinformation system network 2. The transmission unit 150 transmits thecontrol system data in the transmission buffer 140 a (control systemdata transmission buffer) that has not been transmitted yet, and theinformation data in the transmission buffer 140 b (information systemdata transmission buffer) that has not been transmitted yet. Thetransmission unit 150 uses the frame constructing unit 151 to transmitthe data to the network to which it should be transmitted, included in aframe corresponding to the network to which it should be transmitted.The network to which the information system data should be transmittedis the information system network 2, and the network to which thecontrol system data should be transmitted is the control system network1, but in a case where predetermined exception conditions are satisfiedsuch that transmission cannot be performed to the control system network1 (e.g., a case where an abnormality has been detected in at least partof the control system network 1 or the like), this is the informationsystem network 2.

That is to say, the transmission unit 150 performs transmission ofinformation system data by sending out E-frames including thatinformation system data to the information system network 2. In a casewhere predetermined exception conditions are not satisfied, thetransmission unit 150 performs transmission of CAN frames including thatcontrol system data by sending out onto the bus 30 a of the controlsystem network 1, and in a case where the predetermined exceptionconditions are satisfied, performs transmission of E-frames includingthat control system data by sending out onto the information systemnetwork 2. CAN frames including control system data sent out onto thebus 30 a by the transmission unit 150 have been generated by, forexample, including control system data in the data field of a CAN frame,and including the CAN-ID that had been attached to the control systemdata in the transmission buffer in the ID field of the CAN frame. AnE-frame including information system data, that is sent out to the cable20 e by the transmission unit 150, is an E-frame where the payloadincludes, for example, identification flag information representingwhether or not control system data to be transmitted to the controlsystem network 1 is included, the identification flag informationindicating that control system data is not included, and informationsystem data, with the MAC address that had been attached to theinformation system data in the transmission buffer set as thedestination MAC address. An E-frame including control system data, thatis sent out to the cable 20 e by the transmission unit 150, is anE-frame where the payload includes, for example, identification flaginformation representing whether or not control system data to betransmitted to the control system network 1 is included, theidentification flag information indicating that control system data isincluded, and control system data, with a particular MAC address setbeforehand (e.g., a broadcast address, etc.) set as the destination MACaddress. Note that in E-frames transmitted by the transmission unit 150,the identification flag information may be provided in the type in theheader or the like, instead of the payload, and for example, a bit foridentifying whether or not a global MAC address in the destination MACaddress in the header may be used as identification flag information,and set to a value not that of a global MAC address, thereby indicatingthat control system data to be transmitted to the control system network1 is included.

In a case of transmitting data of each of the control system datatransmission buffer and information system data transmission buffer, thetransmission unit 150 performs priority transmission control, where thepriority type data that is one of the control system data (first-typedata) and information system data (second-type data) is transmitted withhigher propriety than non-priority type data that is the other data,based on priority information set in the degree-of-priority setting unit160 (e.g., information for identifying the priority type data regardingwhich of control system data and information system data should betransmitted with priority, or the like). Note that in one example of thepresent embodiment, priority information is set at thedegree-of-priority setting unit 160 indicating that control system datashould be transmitted with priority over the information system data. Ina case where data has been transmitted from the transmission buffers 140a and 140 b by the transmission unit 150, that data is deleted from thetransmission buffer, for example.

The degree-of-priority setting unit 160 sets and stores priorityinformation indicating which of control system data and informationsystem data to give priority to (which has higher priority). Note thatthe priority information may be set such that the control system dataand information system data have the same degree of priority. Thedegree-of-priority setting unit 160 may set the priority information tobe that set beforehand, or may set the priority information so as to bethat based on the state of the vehicle 9 in the past, processing resultsof onboard devices, and so forth.

1.4 Configuration of Hub 200

The hub 200 is configured including, for example, digital circuits suchas a processor, memory, and so forth, analog circuits, communicationcircuits, and so forth, and has a function of transferring (relaying)frames received from one transmission path (bus or cable) to anothertransmission path.

FIG. 7 is a configuration diagram of the hub 200. The hub 200 isconfigured including a reception unit 210 a (first reception unit), areception unit 210 b (second reception unit), a reception buffer 220 a(first reception buffer), a reception buffer 220 b (second receptionbuffer), a selecting unit 230, a transfer rule storing unit 231, atransmission buffer 240 a (first transmission buffer), a transmissionbuffer 240 b (second transmission buffer), a transmission unit 250, anda degree-of-priority setting unit 260. These components are realized bycommunication circuits in the hub 200, a processor or digital circuitsexecuting programs stored in the memory, and so forth.

The reception buffer 220 a, reception buffer 220 b, transmission buffer240 a, and transmission buffer 240 b are each configured of storagemedia such as memory or the like, and are FIFO buffers, for example. Thereception buffer 220 a (first reception buffer) is also referred to as acontrol system data reception buffer, and the transmission buffer 240 a(first transmission buffer) is also referred to as a control system datatransmission buffer. The reception buffer 220 b (second receptionbuffer) is also referred to as an information system data receptionbuffer, and the transmission buffer 240 b (second transmission buffer)is also referred to as an information system data transmission buffer.

The reception unit 210 a sequentially receives CAN frames from the bus30 a of the control system network 1. Each time a CAN frame is received,the reception unit 210 a confirms whether the CAN-ID of the received CANframe is an ID that should be received, based on a reception ID list(see FIG. 6), and if an ID that should be received, stores the contentsof the CAN frame in the reception buffer 220 a. The contents of a CANframe that the reception unit 210 a stores in the reception buffer 220 ais the CAN-ID and size (DLC) and so forth added to data (the contents ofthe data field). A reception ID list used by the hub 200 lists CAN-IDsof CAN frames including data that can be the object of transfer to theinformation system network 2 (e.g., vehicle state data and so forth),for example, and may have different content from the reception ID listused by the X-ECU 100. If the CAN-ID of a received CAN frame is an IDnot shown in the reception ID list, the reception unit 210 a cancelsreception of that CAN frame, and does not store the contents of that CANframe in the reception buffer 220 a.

The reception unit 210 b sequentially receives E-frames from the cable20 f of the information system network 2, and each time an E-frame isreceived, the reception unit 210 b stores the contents of that E-framein the reception buffer 220 b. The contents of an E-frame that thereception unit 210 b stores in the reception buffer 220 b is data(contents of the payload) to which a transmission source MAC address hasbeen added, for example. For example, E-frames that have images andother data from various types of sensors such as the camera 300 b, LIDAR300 c, GPS 300 d, and so forth, in the payloads thereof, are transmittedwith the hub 200 as the destination, or are broadcast, and the receptionunit 210 b receives these E-frames.

The transfer rule storing unit 231 stores transfer rule information thathas been decided beforehand, in a storage medium such as memory or thelike. FIG. 8 illustrates an example of transfer rule information. Thetransfer rule information correlates information of transfer sources andinformation of transfer destinations (addressees), as illustrated inFIG. 7. The example in FIG. 7 shows that in a case where a CAN frame ofCAN-ID 0x100 or 0x101 is received from CAN bus 1, which indicates thebus 30 a, the hub 200 should transfer data that is the content of theCAN frame to a destination that is a device identified by MAC address“00:11:22:33:44:55” on the information system network 2. This also showsthat in a case where a CAN frame of CAN-ID 0x102 is received from CANbus 1, the hub 200 should transfer data that is the content of the CANframe to a destination that is a device identified by MAC address“00:12:23:34:45:56” on the information system network 2. This also showsthat in a case of having received an E-frame of which the transmissionsource MAC address is “00:11:22:33:44:55”, the hub 200 should attach aCAN-ID “0x300” to the data that is the content of that E-frame, andtransfer with the CAN bus 1 as the destination.

The selecting unit 230 is configured including a transfer datagenerating unit 233. The selecting unit 230 selects whether thedestination of data that is the content of one of the reception buffer220 a and reception buffer 220 b is the control system network 1 or theinformation system network 2, based no transfer rule information. Forexample, attaching a transmission source MAC address or destination MACaddress in the header of an E-frame that has been received, to datastored in a reception buffer based on the E-frame, enables the selectingunit 230 to select the destination of the data by the transmissionsource MAC address or destination MAC address, and transfer ruleinformation. Also, attaching a CAN-ID of a CAN frame that has beenreceived to data stored in a reception buffer based on the CAN frameenables the selecting unit 230 to select the destination of the datafrom the CAN-ID and the transfer rule information.

In a case of having selected the control system network 1 as thedestination of data that is the content of one of the reception buffer220 a and reception buffer 220 b, the selecting unit 230 generates datato be transferred (transmitted) by the transfer data generating unit 233based on that data and stores it in the transmission buffer 240 a(control system data transmission buffer), and in a case of havingselected the information system network 2, generates data to betransferred (transmitted) by the transfer data generating unit 233 basedon that data and stores it in the transmission buffer 240 b (informationsystem data transmission buffer). The transfer data generating unit 233can generate data the same as the data that is the content of thereception buffer, for example, as data to be transmitted. In a casewhere the control system network 1 has been selected as the destinationof data that is the content of the information system data receptionbuffer, but the data is of a large size that cannot be stored in thedata field of a CAN frame, the transfer data generating unit 233 cansplit that data into multiple data (data of a size that can be stored inthe data field of a CAN frame), generate the multiple data as the resultof splitting as data to be transmitted, and store in the control systemdata transmission buffer. At the time of storing data in thetransmission buffer, the transfer data generating unit 233 can attachinformation indicating the destination and so forth (transferdestination information in the transfer rule information, etc.) to thatdata. Note that transferring (relaying) of frames by the hub 200 isreception and transmission of data (information) relating to frames, andcan involve conversion of communication method, frame format, and soforth, corresponding to the communication protocol used at thetransmission path that is the transfer destination. The hub 200 also cantransmit one or multiple frames to one or multiple transmission paths inaccordance with one or multiple frames received from one or multipletransmission paths, as transfer of frames among transmission paths.

When selecting the destination of data each time reading out data fromone of the reception buffer 220 a and reception buffer 220 b, andreading out the data, the selecting unit 230 performs priority readoutcontrol, where the contents of a priority reception buffer that is oneof the control system data reception buffer and information system datareception buffer are read out with higher propriety than the contents anon-priority reception buffer that is the other buffer, based onpriority information set in the degree-of-priority setting unit 260(e.g., information for identifying the priority reception buffer fromwhich readout should be performed with priority, or the like). Thedegree-of-priority setting unit 260 stores priority information in aregion of a storage medium such as memory. Note that in one example ofthe present embodiment, priority information is set at thedegree-of-priority setting unit 260 indicating that data of the controlsystem data reception buffer should be read out with priority over theinformation system data reception buffer. In a case where data has beenread out from the reception buffers 220 a and 220 b, that data isdeleted from the reception buffer.

The transmission unit 250 is configured including a frame constructingunit 251 that constructs frames in accordance with the communicationprotocols corresponding to each of the control system network 1 andinformation system network 2. The transmission unit 250 transmits theyet-to-be-transmitted data in the transmission buffer 240 a (controlsystem data transmission buffer), and the yet-to-be-transmitted data inthe transmission buffer 240 b (information system data transmissionbuffer). The transmission unit 250 uses the frame constructing unit 251to transmit the data to the network to which it should be transmitted,included in a frame corresponding to the network to which it should betransmitted. The network to which the data in the system datatransmission buffer should be transmitted is the information systemnetwork 2, and the network to which the data in the control system datatransmission buffer should be transmitted normally is the control systemnetwork 1, but in a case where predetermined exception conditions aresatisfied such that transmission cannot be performed to the controlsystem network 1 (e.g., a case where an abnormality has been detected inat least part of the control system network 1 or the like), this is theinformation system network 2. That is to say, the transmission unit 250performs transmission of data in the information system datatransmission buffer by sending out E-frames including that data to theinformation system network 2. In a case where predetermined exceptionconditions are not satisfied, the transmission unit 250 performstransmission of CAN frames including that data in the control systemdata transmission buffer by sending out onto the bus 30 a of the controlsystem network 1, and in a case where the predetermined exceptionconditions are satisfied, performs transmission of E-frames includingthat data by sending out onto the information system network 2. CANframes including data have been generated by, for example, includingdata to be sent out to the bus 30 a by the transmission unit 250 in thedata field of a CAN frame, and including the CAN-ID that had beenattached to the data in the transmission buffer in the ID field of theCAN frame. An E-frame including data to be sent out to the cable 20 f bythe transmission unit 250, is an E-frame where the payload includes, forexample, identification flag information representing whether or notdata to be transmitted to the control system network 1 is included, theidentification flag information indicating that data to be transmittedto the control system network 1 is not included, and information systemdata, with the MAC address that had been attached to the informationsystem data in the transmission buffer set as the destination MACaddress. An E-frame including data to be sent out to the cable 20 f bythe transmission unit 250, is an E-frame where the payload includes, forexample, identification flag information representing whether or notdata to be transmitted to the control system network 1 is included, theidentification flag information indicating that data to be transmittedto the control system network 1 is included, and control system data,with a particular MAC address set beforehand (e.g., a broadcast address,etc.) set as the destination MAC address. Note that in E-framestransmitted by the transmission unit 250, the identification flaginformation may be provided in the type in the header or the like,instead of the payload, and for example, a bit for identifying whetheror not a global MAC address in the destination MAC address in the headermay be used as identification flag information, and set to a value notthat of a global MAC address, thereby indicating that control systemdata to be transmitted to the control system network 1 is included.

In a case of transmitting data of each of the control system datatransmission buffer and information system data transmission buffer, thetransmission unit 250 performs priority transmission control, where theyet-to-be-transmitted data of a priority transmission buffer that is oneof the control system data transmission buffer and information systemdata reception buffer are transmitted with higher propriety thanyet-to-be-transmitted data of a non-priority transmission buffer that isthe other buffer, based on priority information set in thedegree-of-priority setting unit 260 (e.g., information for identifyingthe priority transmission buffer from the control system datatransmission buffer and information system data transmission buffer,regarding which data should be transmitted with priority, or the like).The priority information is information where a priority transmissionbuffer and priority reception buffer have been correlated, such as forexample, the priority reception buffer is the control system datareception buffer in a case where the priority transmission buffer is thecontrol system data transmission buffer, and the priority receptionbuffer is the information system data reception buffer in a case wherethe priority transmission buffer is the information system datatransmission buffer. Note that in one example of the present embodiment,priority information is set at the degree-of-priority setting unit 260indicating the control system data transmission buffer is thetransmission buffer of which data should be transmitted with priorityover the information system data transmission buffer. In a case wheredata has been transmitted from the transmission buffers 240 a and 240 bby the transmission unit 250, that data is deleted from the transmissionbuffer, for example.

The degree-of-priority setting unit 260 sets and stores priorityinformation indicating which of the control system data reception buffer(or control system data transmission buffer) and information system datareception buffer (or information system data transmission buffer) togive priority to (which has higher priority). Note that the priorityinformation may be set such that the buffers have the same degree ofpriority. The degree-of-priority setting unit 260 may set the priorityinformation to be that set beforehand, or may set the priorityinformation so as to be that based on the state of the vehicle 9 in thepast, processing results of onboard devices, and so forth.

1.5 Operations of X-ECU 100

FIG. 9 is a flowchart illustrating an example of data processing by theX-ECU 100. The X-ECU 100 sequentially stores the contents of framessequentially received by the reception unit 110 a and reception unit 110b from transmission paths in the reception buffer 120 a (control systemdata reception buffer) and reception buffer 120 b (information systemdata reception buffer). The generating unit 130 and transmission unit150 perform the data processing illustrated in FIG. 9, in parallel withthe reception and storage by the reception units 110 a and 110 b. Asthis data processing, the X-ECU 100 performs reception data readoutprocessing (step S1) and transmission data generating processing (stepS2) primarily by the generating unit 130, and data transmissionprocessing (step S3) primarily by the transmission unit 150. This dataprocessing is performed repetitively.

First, the reception data readout processing (step S1) will be describedwith reference to FIG. 10. Assumption will be made here that data storedin the reception buffers 120 a and 120 b by the reception units 110 aand 110 b is deleted from the reception buffers upon being read out bythe generating unit 130.

The generating unit 130 of the X-ECU 100 confirms whether data is storedin the control system data reception buffer (step S101), and confirmswhether data is stored in the information system data reception buffer(step S102). In a case where no data is stored in either of thereception buffers, the generating unit 130 repeats the processing ofsteps S101 and S102 (step S103).

If data is stored in both of the control system data reception bufferand information system data reception buffer (step S104), the generatingunit 130 confirms whether there is data present in the reception buffersthat has not been read out for a certain amount of time (step S105).Confirmation in step S105 is performed based on calculating the unreadtime of data (time not read out), and confirming whether or not theunread time has exceeded a certain threshold value, for example.

In a case where there is no data that has not been read out for acertain amount of time as the result of the confirmation in step S105,the generating unit 130 references priority information, confirmsreadout from which reception buffer should be given priority, and in acase where the degree of priority is higher for readout from the controlsystem data reception buffer (step S106) data is read out from thecontrol system data reception buffer (step S107). In a case where thedegree of priority is higher for readout from the information systemdata reception buffer (step S108), the generating unit 130 reads outdata from the information system data reception buffer (step S109). In acase where the degree of priority is the same, the generating unit 130reads out the oldest data of the data in both reception buffers (stepS110). Note that in an example where the priority information is setsuch that readout is performed from the control system data receptionbuffer with priority (i.e., the control system data reception buffer isset as a priority reception buffer where the degree of priority is high,and the information system data reception buffer is set as anon-priority reception buffer where the degree of priority is low), thegenerating unit 130 reads out data from the control system datareception buffer in step S107 in a case of having confirmed in step S105that there is no data that has not been read out for a certain amount oftime.

In a case where there is data that has not been read out for a certainamount of time as the result of the confirmation in step S105, thegenerating unit 130 reads out that data (step S110). Also, in a casewhere confirmation is made in step S104 that data is stored in only oneof the control system data reception buffer and information system datareception buffer, the generating unit 130 reads out the oldest data inthe one reception buffer (step S110).

Although description has been made there that data read out by thegenerating unit 130 is deleted from the reception buffers, data may bemanaged in the reception buffers by a method other than deletion, aslong as it can be distinguished from data that has not been read out(unread data). Regardless of which method is used to manage data, thegenerating unit 130 performs priority readout control where data is readout of the priority reception buffer that is one of the control systemdata reception buffer and information system data reception buffer withpriority, as compared to the non-priority buffer that is the other. Asfor the priority readout control, the generating unit 130 repeatedlyconfirms the reception buffer 120 a (control system data receptionbuffer) and reception buffer 120 b (information system data receptionbuffer), and in a case where unread data exists in the control systemdata reception buffer and unread data exists in the information systemdata reception buffer when confirming, reads out the unread data in thepriority reception buffer in a case where the readout time of unreaddata in the non-priority reception buffer does not exceed a certainthreshold value, and reads out the unread data in the non-priorityreception buffer in a case where the readout time of unread data exceedsthe certain threshold value. Also, when confirming the receptionbuffers, in a case where there is unread data in the control system datareception buffer and there is no unread data in the information systemdata reception buffer, the generating unit 130 reads out the unread datain the information system data reception buffer. Also, when confirmingthe reception buffers, in a case where there is no unread data in thecontrol system data reception buffer and there is unread data in theinformation system data reception buffer, the generating unit 130 readsout the unread data in the control system data reception buffer. Theabove-described certain threshold value may be decided based on thestate of the vehicle 9 in the past, the processing results of onboarddevices, and so forth. It is suitable to set the above-described certainthreshold value to an appropriate time that is longer than the timerequired to read out one worth of data in the priority reception buffer,in order to prevent a situation where no data is read out from thenon-priority reception buffer at all due to consecutive readout of datafrom the priority reception buffer in the priority readout control.

Next, transmission data generating processing (step S2) will bedescribed with reference to FIG. 11. The generating unit 130 obtainsvehicle state (step S201), or obtains sensor information (step S202),based on data read out from one of the reception buffers. Next, thegenerating unit 130 performs detection regarding various types of itemsrelating to the surrounding environment of the vehicle 9 and the stateof the vehicle 9 and so forth, based on the obtained vehicle state orsensor information (step S203). Note that when performing detection instep S203 relating to the environment, based on the vehicle state andsensor information and so forth obtained based on data read out from oneof the reception buffers in step S201 or step S202, the generating unit130 may further perform detection by referencing one or multiple dataread out from the reception buffers during a certain previous timeperiod (e.g., within several seconds) or the like.

Next, the generating unit 130 judges whether or not traveling control ofthe vehicle 9 is necessary (step S204), based on the detection resultsin step S203. In a case of having judged that traveling control of thevehicle 9 is necessary, the generating unit 130 generates vehiclecontrol data as control system data (first-type data) (step S205), setsa CAN-ID that can operate as a degree of priority of a CAN frame, to beattached to this vehicle control data (step S206), and writes thiscontrol system data to the transmission buffer 140 a (control systemdata transmission buffer) (step S207). In a case of having judged thattraveling control of the vehicle 9 is unnecessary in step S204, thegenerating unit 130 skips the processing of steps S205 through S207.

Next, the generating unit 130 judges whether or not control of sensorsinstalled in the vehicle 9 is necessary, based on the detection resultsin step S203 (step S208). In a case of having judged that sensor controlis necessary, the generating unit 130 generates sensor control data asinformation system data (second-type data) (step S209), sets destinationinformation such as a MAC address or the like serving as the destinationof the sensor control data, to be attached to this sensor control data(step S210), and writes this information system data to the transmissionbuffer 140 b (information system data transmission buffer) (step S211).In a case of having judged that sensor control is unnecessary in stepS208, the generating unit 130 skips the processing of steps S209 throughS211.

Next, the data transmission processing (step S3) will be described withreference to FIGS. 12 and 13. When the data stored in the transmissionbuffers 140 a and 140 b is read out by the transmission unit 150 andtransmitted, the data is deleted from the transmission buffers.

The transmission unit 150 of the X-ECU 100 confirms whether there isdata stored in the control system data transmission buffer (step S301),and confirms whether there is data stored in the information system datatransmission buffer (step S302). While there is no data stored in eitherof the transmission buffers, the transmission unit 150 repeats theprocessing of step S301 and step S302 (step S303).

If data is stored in both of the control system data transmission bufferand information system data transmission buffer (step S304), thetransmission unit 150 confirms whether there is data in the transmissionbuffers that has not been transmitted for a certain amount of time (stepS305). Confirmation in step S305 is performed based on calculating thenon-transmission time of data (time not transmitted), and confirmingwhether or not the non-transmission time has exceeded a predeterminedthreshold value, for example.

In a case where there is no data that has not been transmitted for acertain amount of time as the result of the confirmation in step S305,the transmission unit 150 references priority information, confirmstransmission from which transmission buffer should be given priority,and in a case where the degree of priority to transmit the controlsystem data, i.e., the degree of priority for transmission of data fromthe control system data transmission buffer, is higher (step S306),control system data is read out from the control system datatransmission buffer, and the data is identified as being the object oftransmission (step S307). In a case where the degree of priority totransmit the information system data, i.e., the degree of priority fortransmission of data from the information system data transmissionbuffer, is higher (step S308), the transmission unit 150 reads outinformation system data from the information system data transmissionbuffer, and identifies this data as being the object of transmission(step S309). In a case where the degree of priority is the same, thetransmission unit 150 reads out the oldest data of the data in bothtransmission buffers and identifies it as being the object oftransmission (step S310). Note that in an example where the priorityinformation is set such that transmission is performed from the controlsystem data (data within the control system data transmission buffer)with priority (i.e., the control system data is set as priority typedata where the degree of priority is high, and the information systemdata is set as a non-priority type data where the degree of priority islow, or the control system data transmission buffer is set as a prioritytransmission buffer where the degree of priority is high, and theinformation system data transmission buffer is set as a non-prioritytransmission buffer where the degree of priority is low), and in a caseof having confirmed in step S305 that there is no data that has not beentransmitted for a certain amount of time, the transmission unit 150reads out control system data from the control system data transmissionbuffer, and identifies this data as being the object of transmission instep S307.

In a case where there is data that has not been transmitted for acertain amount of time as the result of the confirmation in step S305,the transmission unit 150 reads out that data and identifies as beingthe object of transmission (step S310). Also, in a case whereconfirmation is made in step S304 that data is stored in only one of thecontrol system data transmission buffer and information system datatransmission buffer, the transmission unit 150 reads out the oldest datain the one transmission buffer and identifies it as being the object oftransmission (step S310).

Once data that is the object of transmission has been identified in stepS307, S309, or S310, the transmission unit 150 determines whether theobject of transmission is control system data or information system data(step S311), and if control system data, determines whether or notpredetermined exception conditions where transmission cannot be made tothe control system network 1 are satisfied (e.g., whether or not anabnormality has been detected at part of the control system network 1)(step S312).

In a case where determination is made that the predetermined exceptionconditions are satisfied due to an abnormality having been detected atpart of the control system network 1 or the like in step S312, thetransmission unit 150 constructs an E-frame including control systemdata identified as being the object of transmission, and transmits thisE-frame to the information system network 2 (step S313). On the otherhand, in a case where determination is made that the predeterminedexception conditions are not satisfied in step S312, the transmissionunit 150 constructs a CAN frame including the control system data thathas been identified as the object of transmission, and transmits thisCAN frame to the control system network 1 (step S314).

In a case where determination has been made in step S311 that the objectof transmission is information system data, the transmission unit 150constructs an E-frame including the information system data identifiedas being the object of transmission, and transmits this E-frame to theinformation system network 2 (step S315).

Although description has been made here that data read out andtransmitted by the transmission unit 150 is deleted from thetransmission buffers, data may be managed in the transmission buffers bya method other than deletion, as long as it can be distinguished fromdata that has not been transmitted (yet-to-be-transmitted data).Regardless of which method is used to manage data, the transmission unit150 performs priority transmission control where priority type data thatis one of the control system data and information system data is sentwith priority, as compared to the non-priority type data that is theother. As for the priority transmission control, the transmission unit150 repeatedly confirms the transmission buffer 140 a (control systemdata transmission buffer) and transmission buffer 140 b (informationsystem data transmission buffer), and in a case whereyet-to-be-transmitted control system data exists in the control systemdata transmission buffer and yet-to-be-transmitted information systemdata exists in the information system data transmission buffer whenconfirming, transmits the priority type data in a case where thenon-transmission time of the non-priority type data does not exceed apredetermined threshold value, and transmits the non-priority type datain a case where the non-transmission time exceeds the predeterminedthreshold value. Also, when confirming the transmission buffers, in acase where there is yet-to-be-transmitted control system data in thecontrol system data priority type buffer and there isyet-to-be-transmitted information system data in the information systemdata transmission buffer, the transmission unit 150 transmits thecontrol system data. Also, when confirming the transmission buffers, ina case where there is no yet-to-be-transmitted control system data inthe control system data transmission buffer and there isyet-to-be-transmitted information system data in the information systemdata transmission buffer, the transmission unit 150 transmits theinformation system data. The above-described predetermined thresholdvalue may be decided based on the state of the vehicle 9 in the past,the processing results of onboard devices, and so forth. It is suitableto set the above-described certain threshold value to an appropriatetime that is longer than the time required to transmit one worth ofpriority type data, in order to prevent a situation where no prioritytype data is transmitted at all due to consecutive transmission ofpriority type data in the priority transmission buffer.

1.6 Operations of Hub 200

FIG. 14 is a flowchart illustrating an example of data processing by thehub 200. The hub 200 sequentially stores the contents of framessequentially received by the reception unit 210 a and reception unit 210b from transmission paths in the reception buffer 220 a (control systemdata reception buffer) and reception buffer 220 b (information systemdata reception buffer). The selecting unit 230 and transmission unit 250perform the data transfer processing illustrated in FIG. 14, in parallelwith the reception and storage by the reception units 210 a and 210 b.As this data transfer processing, the hub 200 performs reception datareadout processing (step S1) and transfer data generating processing(step S4) primarily by the selecting unit 230, and data transmissionprocessing (step S3) primarily by the transmission unit 250. This datatransferring processing is performed repetitively. Note that thereception data readout processing by the selecting unit 230 is the sameas the reception data readout processing by the generating unit 130 ofthe X-ECU 100 (FIG. 10), and the data transmission processing by thetransmission unit 250 is the same as the data transmission processing bythe transmission unit 150 of the X-ECU 100 (FIGS. 12 and 13), sodescription of this processing will be omitted as appropriate.

Once data stored in the reception buffers 220 a and 220 b by thereception units 210 a and 210 b of the hub 200 has been read out by theselecting unit 230, that data is deleted from the reception buffers.

The selecting unit 230 of the hub 200 repeatedly confirms whether thereis data stored in the control system data reception buffer andinformation system data reception buffer, as illustrated in FIG. 10(steps S101 through S103).

When data is stored in both reception buffers (step S104), the selectingunit 230 confirms whether there is data in a reception buffer that hasnot been read out for a certain amount of time (step S105).

In a case where there is no data that has not been read out for acertain amount of time as the result of the confirmation in step S105,the selecting unit 230 references priority information, and in a casewhere the degree of priority is higher for readout from the controlsystem data reception buffer (step S106) data is read out from thecontrol system data reception buffer (step S107). In a case where thedegree of priority is higher for readout from the information systemdata reception buffer (step S108), the selecting unit 230 reads out datafrom the information system data reception buffer (step S109).

In a case where there is data that has not been read out for a certainamount of time as the result of the confirmation in step S105, theselecting unit 230 reads out that data (step S110). Also, in a casewhere confirmation is made in step S104 that data is stored in only oneof the control system data reception buffer and information system datareception buffer, the oldest data in the one reception buffer is readout (step S110).

Although description has been made here that data read out by theselecting unit 230 is deleted from the reception buffers, data may bemanaged in the reception buffers by a method other than deletion, aslong as it can be distinguished from data that has not been read out(unread data). Regardless of which method is used to manage data, theselecting unit 230 performs priority readout control where data is readout from the priority reception buffer that is one of the control systemdata reception buffer and information system data reception buffer withpriority, as compared to the non-priority reception buffer that is theother. As for the priority readout control, the selecting unit 230repeatedly confirms the reception buffer 220 a (control system datareception buffer) and reception buffer 220 b (information system datareception buffer), and in a case where unread data exists in the controlsystem data reception buffer and unread data exists in the informationsystem data reception buffer when confirming, reads out the unread datain the priority reception buffer when the readout time of unread data inthe non-priority reception buffer does not exceed a certain thresholdvalue, and reads out the unread data in the non-priority receptionbuffer when the readout time exceeds the certain threshold value. Also,when confirming the reception buffers, in a case where there is unreaddata in the control system data reception buffer and there is no unreaddata in the information system data reception buffer, the selecting unit230 reads out the unread data in the control system data receptionbuffer. Also, when confirming the reception buffers, in a case wherethere is no unread data in the control system data reception buffer andthere is unread data in the information system data reception buffer,the selecting unit 230 reads out the unread data in the informationsystem data reception buffer.

Next, the transfer data generating processing (step S4) by the selectingunit 230 will be described with reference to FIG. 15. Regarding the dataread out form one of the reception buffers, the selecting unit 230selects whether the destination (transfer destination) of that data isthe control system network 1 or the information system network 2, basedon transfer rule information (step S401).

Next, in a case where the data regarding which the destination has beenselected is data read out from the information system data receptionbuffer (step S402), and the information system network 2 has beenselected as the destination (step S403), the selecting unit 230generates transfer data (data to be transferred) including that data,based on that data (step S404), and writes the generated data to thetransmission buffer 240 b (information system data transmission buffer)(step S405). In a case where the control system network 1 has beenselected as the destination of data that has been read out from theinformation system data reception buffer in step S403, and that data isof a size that cannot be stored in a CAN data frame, the selecting unit230 splits the data into multiple data (step S406). The selecting unit230 then generates transfer data to include each of the data obtained asa result of the splitting (step S407), and writes each generatedtransfer data to the transmission buffer 240 a (control system datatransmission buffer) (step S408).

In a case where determination is made in step S402 that the dataregarding which the destination has been selected is data read out fromthe control system data reception buffer, and the control system network1 has been selected as the destination (step S409), the selecting unit230 generates transfer data including that data, based on that data(step S410), and writes the generated data to the transmission buffer240 a (control system data transmission buffer) (step S411). When thedestination of the data read out from the control system data receptionbuffer is selected to be the information system network 2 in step S409,the selecting unit 230 generates transfer data including that data (stepS412), and writes the generated transfer data to the transmission buffer240 b (information system data transmission buffer) (step S413).

Next, the data transmission processing by the transmission unit 250(step S3) will be described with reference to FIGS. 12 and 13. When thedata stored in the transmission buffers 240 a and 240 b is read out bythe transmission unit 250 and transmitted, the data is deleted from thetransmission buffers.

The transmission unit 250 of the hub 200 repeatedly confirms whetherthere is data stored in the control system data transmission buffer andinformation system data transmission buffer (steps S301 through S303).

If data is stored in both of the transmission buffers (step S304), thetransmission unit 250 confirms whether there is data in the transmissionbuffers that has not been transmitted for a certain amount of time (stepS305).

In a case where there is no data that has not been transmitted for acertain amount of time as the result of the confirmation in step S305,the transmission unit 250 references priority information, confirmstransmission of data from which transmission buffer should be givenpriority, and in a case where the degree of priority is higher for thecontrol system data transmission buffer (step S306), data is read outfrom the control system data transmission buffer, and this data isidentified as being the object of transmission (step S307). In a casewhere the degree of priority is higher for the information system datatransmission buffer (step S308), the transmission unit 250 reads outdata from the information system data transmission buffer, andidentifies this data as being the object of transmission (step S309).Note that in an example where the priority information is set such thatthe control system data transmission buffer is the priority transmissionbuffer with a high degree of priority, and the information system datatransmission buffer is the non-priority transmission buffer with a lowdegree of priority, and in a case of having confirmed in step S305 thatthere is no data that has not been transmitted for a certain amount oftime, the transmission unit 250 reads out control system data from thecontrol system data transmission buffer, and identifies this data asbeing the object of transmission in step S307.

In a case where there is data that has not been transmitted for acertain amount of time as the result of the confirmation in step S305,the transmission unit 250 reads out that data and identifies as beingthe object of transmission (step S310). Also, in a case whereconfirmation is made in step S304 that data is stored in only one of thecontrol system data transmission buffer and information system datatransmission buffer, the transmission unit 250 reads out the oldest datain the one transmission buffer and identifies this as being the objectof transmission (step S310).

Once data that is the object of transmission has been identified in stepS307, S309, or S310, the transmission unit 250 determines whether theobject of transmission is data of the control system data transmissionbuffer or data of the information system data transmission buffer (stepS311), and if data of the control system data transmission buffer,determines whether or not predetermined exception conditions wheretransmission cannot be made to the control system network 1 aresatisfied (step S312).

In a case where determination is made that the predetermined exceptionconditions are satisfied due to an abnormality having been detected atpart of the control system network 1 or the like in step S312, thetransmission unit 250 constructs an E-frame including data identified asbeing the object of transmission, and transmits this E-frame to theinformation system network 2 (step S313). On the other hand, in a casewhere determination is made that the predetermined exception conditionsare not satisfied in step S312, the transmission unit 250 constructs aCAN frame including the data that has been identified as the object oftransmission, and transmits this CAN frame to the control system network1 (step S314).

In a case where determination has been made in step S311 that the objectof transmission is data of the information system data transmissionbuffer, the transmission unit 250 constructs an E-frame including thedata identified as being the object of transmission, and transmits thisE-frame to the information system network 2 (step S315).

Although description has been made here that data read out andtransmitted by the transmission unit 250 is deleted from thetransmission buffers, data may be managed in the transmission buffers bya method other than deletion, as long as it can be distinguished fromdata that has not been transmitted (yet-to-be-transmitted data).Regardless of which method is used to manage data, the transmission unit250 performs priority transmission control where data is transmittedfrom the priority transmission buffer that is one of the control systemdata transmission buffer and information system data transmission bufferwith priority, as compared to the non-priority transmission buffer thatis the other. As for the priority transmission control, the transmissionunit 250 repeatedly confirms the transmission buffer 240 a (controlsystem data transmission buffer) and transmission buffer 240 b(information system data transmission buffer), and in a case whereyet-to-be-transmitted data exists in the control system datatransmission buffer and yet-to-be-transmitted data exists in theinformation system data transmission buffer when confirming, transmitsthe data in the priority transmission buffer in a case where thenon-transmission time of the non-priority transmission buffer does notexceed a predetermined threshold value, and transmits the data in thenon-priority transmission buffer in a case where the non-transmissiontime exceeds the predetermined threshold value. Also, when confirmingthe transmission buffers, in a case where there is yet-to-be-transmitteddata in the control system data transmission buffer and there isyet-to-be-transmitted data in the information system data transmissionbuffer, the transmission unit 250 transmits the data in that controlsystem data transmission buffer. Also, when confirming the transmissionbuffers, in a case where there is no yet-to-be-transmitted data in thecontrol system data transmission buffer and there isyet-to-be-transmitted data in the information system data transmissionbuffer, the transmission unit 250 transmits the data in that informationsystem data transmission buffer.

1.7 Processing Sequence by ADAS Function of X-ECU 100

FIG. 16 illustrates an example of a processing sequence by the ADASfunction of the X-ECU 100. The X-ECU 100 receives a CAN frame indicatingvehicle state data that the C-ECU 500 a has transmitted over the controlsystem network 1 (step S1001), and receives an E-frame indicating ataken image that is sensor information, transmitted by the camera 300 bon the information system network 2 (step S1002).

The X-ECU 100 performs detection of the surrounding environment of thevehicle 9 based on the vehicle state data and taken image (step S1003),and depending on the results of detection, generates vehicle controldata for example (step S1004), and transmits the vehicle control data tothe bus 30 a of the control system network 1 (step S1005).

1.8 Communication Sequence Relating to Transfer Functions of Hub 200

FIG. 17 illustrates an example of a communication sequence relating tothe transfer functions of the hub 200. Assumption will be made here thatthe degree of priority of the control system data reception buffer (orcontrol system data transmission buffer) is set higher than theinformation system data reception buffer (or information system datatransmission buffer) as priority information at the hub 200.

The hub 200 receives an E-frame including sensor information from theinformation system network 2 (step S1011), and receives a CAN frameincluding vehicle state data from the control system network 1 (stepS1012).

The hub 200 confirms the reception buffers 220 a and 220 b, reads outvehicle state data from the reception buffer 220 a with priority,selects the information system network 2 as being the destination, andtransmits the E-frame including that vehicle state data to theinformation system network 2 (step S1013). The hub 200 also receives aCAN frame including the vehicle state data from the control systemnetwork 1 (step S1014).

The hub 200 confirms the reception buffers 220 a and 220 b, reads outvehicle state data from the reception buffer 220 a with priority,selects the information system network 2 as being the destination, andtransmits the E-frame including that vehicle state data to theinformation system network 2 (step S1015). The hub 200 confirms thereception buffers 220 a and 220 b, and since there is no data in thereception buffer 220 a, reads out sensor information from the receptionbuffer 220 b, selects the destination as being the control systemnetwork 1, and transmits a CAN frame including that sensor informationto the control system network 1 (step S1016).

1.9 Advantages of First Embodiment

In the onboard network system 10 according to the first embodiment, theX-ECU 100 that is an ECU connected to both the first network (controlsystem network 1) and second network (information system network 2) thathave different communication protocols from each other reads out datafrom a reception buffer from one of the networks with priority, orperforms transmission of data from a transmission buffer of which thedestination is one of the networks, in accordance with priorityinformation. Also, the hub 200 connected to both networks reads out datafrom a reception buffer from one of the networks with priority, orperforms transmission of data from a transmission buffer of which thedestination is one of the networks, in accordance with priorityinformation. Accordingly, the order of priority of processing based ondata readout or transmission processing or the like can be made tocorrespond to the importance or the like of data transmitted over thenetworks. Accordingly, transmission of data relating to travelingcontrol of the vehicle 9 can be given priority over transmission ofimage data and so forth, for example, and a situation where transmissionof large-sized data, such as image data and so forth, adversely affectssafe traveling of the vehicle 9 or the like, can be prevented.

Also, in the onboard network system 10 according to the firstembodiment, the X-ECU 100 or hub 200 has a function where, in a casewhere determination is made that predetermined exception conditions aresatisfied by an abnormality being detected at a part of the controlsystem network 1 or the like, an E-frame including the data to betransmitted to the control system network 1 and also includingidentification flag information to that effect is constructed, and theE-frame is transmitted to the information system network 2. There can becases where multiple network paths are secured in the onboard network11, so even if there is an abnormality in part of the control systemnetwork 1, there is a possibility that the X-ECU 100 or hub 200 will beable to transmit data to the device that is the final destination viathe information system network 2. As multiple relay devices connectingthe control system network 1 and information system network 2 can existin the onboard network system 10, an arrangement may be made where oneof the relay devices distinguishes identification flag information of anE-frame, and in a case where the E-frame includes information thatshould be transmitted to the control system network 1, that E-frame maybe subjected to protocol conversion and transferred to the controlsystem network 1. Note that even in a case of having detected that thereis an abnormality at part of the information system network 2, the X-ECU100 or hub 200 do not transmit data, of which the destination is theinformation system network 2, to the control system network 1. Thereason is that data to be transmitted to the information system network2 is generally large in data size, so transmitting this to the controlsystem network 1 would cause delay in transmission of vehicle controldata and so forth on the control system network 1 due to congestion.

1.10 Modification of First Embodiment

The above-described X-ECU 100 (or hub 200) may perform reception datareadout processing (step S1 a) illustrated in FIG. 18, instead of thereception data readout processing (step S1) by the generating unit 130(or selecting unit 230) illustrated in FIG. 10.

The reception data readout processing in FIG. 18 is a modification wherethe step S105 in the reception data readout processing in FIG. 10 hasbeen changed to step S105 a.

In step S105, the generating unit 130 (or selecting unit 230) confirmswhether there is data present in the reception buffers that has not beenread out for a certain amount of time, but in step S105 a, confirmationis made regarding whether a certain quantity of data has already beenread out from the reception buffer of which the degree of priority ishigh (priority reception buffer).

Thus, the generating unit 130 of the X-ECU 100 performs priority readoutcontrol where data is read out from a priority reception buffer that isone of the control system data reception buffer and the informationsystem data reception buffer is given priority over a non-priorityreception buffer that is the other, as follows for example. That is tosay, the generating unit 130 repeatedly confirms the reception buffer120 a (control system data reception buffer) and reception buffer 120 b(information system data reception buffer), and in a case where unreaddata is present in the control system data reception buffer and alsounread data is present in the information system data reception bufferwhen confirming, reads a certain quantity of unread data out from thepriority reception buffer, and thereafter reads out one unread data fromthe non-priority reception buffer. Also, in a case where unread data ispresent in the control system data reception buffer but there is nounread data present in the information system data reception buffer whenconfirming the reception buffers, the generating unit 130 reads out theunread data in the control system data reception buffer. Also, in a casewhere there is no unread data present in the control system datareception buffer but unread data is present in the information systemdata reception buffer when confirming the reception buffers, thegenerating unit 130 reads out the unread data in the information systemdata reception buffer.

Also, the selecting unit 230 of the hub 200 performs priority readoutcontrol where data is read out from a priority reception buffer that isone of the control system data reception buffer and the informationsystem data reception buffer is given priority over a non-priorityreception buffer that is the other, as follows for example. That is tosay, the selecting unit 230 repeatedly confirms the reception buffer 220a (control system data reception buffer) and reception buffer 220 b(information system data reception buffer), and in a case where unreaddata is present in the control system data reception buffer and alsounread data is present in the information system data reception bufferwhen confirming, reads a certain quantity of unread data out from thepriority reception buffer, and thereafter reads out one unread data fromthe non-priority reception buffer. Also, in a case where unread data ispresent in the control system data reception buffer but there is nounread data present in the information system data reception buffer whenconfirming the reception buffers, the selecting unit 230 reads out theunread data in the control system data reception buffer. Also, in a casewhere there is no unread data present in the control system datareception buffer but unread data is present in the information systemdata reception buffer when confirming the reception buffers, theselecting unit 230 reads out the unread data in the information systemdata reception buffer.

The above-described certain quantity may be decided based on the stateof the vehicle 9 in the past, processing results of onboard devices, andso forth. The predetermined quantity is described above may be decidedto be, for example, a quantity greater than one worth of the data in thepriority reception buffer (e.g., a count of two or more data whenexpressing the quantity by a count, or a data amount that is twice ormore the size of one worth when expressing the quantity by data amount),in order to prevent a situation where no data is read out at all fromthe non-priority reception buffer due to consecutive readout of datafrom the priority reception buffer in priority reception control.

Also, the above-described X-ECU 100 (or hub 200) may perform datatransmission processing (step S3 a) illustrated in FIGS. 19 and 13,instead of the data transmission processing (step S3) exemplarilyillustrated in FIGS. 12 and 13 that is carried out by the transmissionunit 150 (or transmission unit 250).

The data transmission processing in FIGS. 19 and 13 is a modificationwhere step S305 in the data transmission processing in FIGS. 12 and 13has been replaced by step S305 a.

In step S305, the transmission unit 150 (or transmission unit 250)confirms whether there is data present in the transmission buffers thathas not been transmitted for a certain amount of time, but in step S305a, confirmation is made regarding whether a certain quantity of data(priority type data) has already been transmitted from the transmissionbuffer of which the degree of priority is high (priority receptionbuffer).

Thus, the transmission unit 150 of the X-ECU 100 performs prioritytransmission control where a priority type data that is one of the oneof the control system data and information system data is transmittedwith priority over non-priority type data that is the other, as followsfor example. That is to say, the transmission unit 150 repeatedlyconfirms the transmission buffer 140 a and transmission buffer 140 b,and in a case where yet-to-be-transmitted control system data is presentin the transmission buffer 140 a and also yet-to-be-transmittedinformation system data is present in the transmission buffer 140 b whenconfirming, transmits a certain quantity of priority type data of thatcontrol system data and information system data, and thereaftertransmits one non-priority type data. Also, in a case whereyet-to-be-transmitted control system data is present in the transmissionbuffer 140 a but there is no yet-to-be-transmitted information systemdata present in the transmission buffer 140 b when confirming thetransmission buffers, the transmission unit 150 transmits that controlsystem data. Also, in a case where there is no yet-to-be-transmittedcontrol system data present in the transmission buffer 140 a butyet-to-be-transmitted data is present in the transmission buffer 140 bwhen confirming the transmission buffers, the transmission unit 150transmits that information system data.

Also, the transmission unit 250 of the hub 200 performs prioritytransmission control where a priority type data that is one of thecontrol system data and information system data is transmitted withpriority over non-priority type data that is the other, as follows forexample. That is to say, the transmission unit 250 repeatedly confirmsthe transmission buffer 240 a and transmission buffer 240 b, and in acase where yet-to-be-transmitted data is present in the transmissionbuffer 240 a and also yet-to-be-transmitted data is present in thetransmission buffer 240 b when confirming, transmits a certain quantityof data in the priority transmission buffer, and thereafter transmitsone data from the non-priority transmission buffer. Also, in a casewhere yet-to-be-transmitted data is present in the transmission buffer240 a but there is no yet-to-be-transmitted data present in thetransmission buffer 240 b when confirming the transmission buffers, thetransmission unit 250 transmits the data that is present. Also, in acase where there is no yet-to-be-transmitted data present in thetransmission buffer 240 a but yet-to-be-transmitted data is present inthe transmission buffer 240 b when confirming the transmission buffers,the transmission unit 250 transmits the data that is present.

The above-described certain quantity may be decided based on the stateof the vehicle 9 in the past, processing results of onboard devices, andso forth. The above-described predetermined quantity may be decided tobe, for example, an appropriate quantity greater than one worth of thedata in the priority transmission buffer (e.g., a count of two or moredata when expressing the quantity by a count, or a data amount that istwice or more the size of one worth when expressing the quantity by dataamount), in order to avoid a situation where no data (non-priority typedata) is transmitted at all from the non-priority buffer due toconsecutive transmission of data (priority type data) from the prioritytransmission buffer in priority transmission control.

Also, the generating unit 130 of the X-ECU 100 may change the priorityreadout control in the reception data readout processing (step S1)illustrated in FIG. 10 or the reception data readout processing (step S1a) illustrated in FIG. 18 as follows. That is to say, the generatingunit 130 repeatedly confirms the reception buffer 120 a (control systemdata reception buffer) and reception buffer 120 b (information systemdata reception buffer), and in a case where unread data is present inthe control system data reception buffer and also unread data is presentin the information system data reception buffer when confirming, readsout the unread data in the priority reception buffer. Also, in a casewhere unread data is present in the control system data reception bufferbut there is no unread data present in the information system datareception buffer when confirming the reception buffers, the generatingunit 130 reads out the unread data in the control system data receptionbuffer. Also, in a case where there is no unread data present in thecontrol system data reception buffer but unread data is present in theinformation system data reception buffer when confirming the receptionbuffers, the generating unit 130 reads out the unread data in theinformation system data reception buffer.

Also, the transmission unit 150 of the X-ECU 100 may change the prioritytransmission control in the data transmission processing (step S3)illustrated in FIGS. 12 and 13 or the data transmission processing (stepS3 a) illustrated in FIGS. 19 and 13 as follows. That is to say, thetransmission unit 150 repeatedly confirms the transmission buffer 140 aand transmission buffer 140 b, and in a case where yet-to-be-transmittedcontrol system data is present in the transmission buffer 140 a and alsoyet-to-be-transmitted information system data is present in thetransmission buffer 140 b when confirming, transmits the priority typedata of the control system data and information system data. Also, in acase where yet-to-be-transmitted control system data is present in thetransmission buffer 140 a but there is no yet-to-be-transmittedinformation system data present in the transmission buffer 140 b whenconfirming the transmission buffers, the transmission unit 150 transmitsthe control system data. Also, in a case where there is noyet-to-be-transmitted control system data present in the transmissionbuffer 140 a but yet-to-be-transmitted information system data ispresent in the transmission buffer 140 b when confirming thetransmission buffers, the transmission unit 150 transmits theinformation system data.

Also, the selecting unit 230 of the hub 200 may change the priorityreadout control in the reception data readout processing (step S1)illustrated in FIG. 10 or the reception data readout processing (step S1a) illustrated in FIG. 18 as follows. That is to say, the selecting unit230 repeatedly confirms the reception buffer 220 a (control system datareception buffer) and reception buffer 220 b (information system datareception buffer), and in a case where unread data is present in thecontrol system data reception buffer and also unread data is present inthe information system data reception buffer when confirming, reads outthe unread data in the priority reception buffer. Also, in a case whereunread data is present in the control system data reception buffer butthere is no unread data present in the information system data receptionbuffer when confirming the reception buffers, the selecting unit 230reads out the unread data in the control system data reception buffer.Also, in a case where there is no unread data present in the controlsystem data reception buffer but unread data is present in theinformation system data reception buffer when confirming the receptionbuffers, the selecting unit 230 reads out the unread data in theinformation system data reception buffer. Also, the hub 200 may performpriority transmission control where transfer of data read out from thepriority reception buffer indicated by priority information (datatransmission based on the data) with priority over transfer of data readout from the non-priority reception buffer.

Also, the transmission unit 250 of the hub 200 may change the prioritytransmission control in the data transmission processing (step S3)illustrated in FIGS. 12 and 13 or the data transmission processing (stepS3 a) illustrated in FIGS. 19 and 13 as follows. That is to say, thetransmission unit 250 repeatedly confirms the transmission buffer 240 aand transmission buffer 240 b, and in a case where yet-to-be-transmitteddata is present in the transmission buffer 240 a and alsoyet-to-be-transmitted data is present in the transmission buffer 240 bwhen confirming, transmits the data in the priority transmission buffer.Also, in a case where yet-to-be-transmitted data is present in thetransmission buffer 240 a but there is no yet-to-be-transmitted datapresent in the transmission buffer 240 b when confirming thetransmission buffers, the transmission unit 250 transmits the data thatis present. Also, in a case where there is no yet-to-be-transmitted datapresent in the transmission buffer 240 a but yet-to-be-transmitted datais present in the transmission buffer 240 b when confirming thetransmission buffers, the transmission unit 250 transmits the data thatis present.

Second Embodiment

A second embodiment where the configuration of the onboard networksystem 10 illustrated in the first embodiment (see FIG. 2) has beenpartially modified will be described below.

2.1 Configuration of Onboard Network System 10 a

FIG. 20 is a diagram illustrating a schematic configuration of anonboard network system 10 a. The hub 200 in the onboard network system10 illustrated in the first embodiment was connected to one CAN bus ofthe control system network 1. In comparison with this, a hub 200 a whichis a partial modification of the hub 200 is connected to two busses,which are the buses 30 a (CAN bus 1) and 30 b (CAN bus 2) in the onboardnetwork system 10 a, as illustrated in FIG. 20. Components of theonboard network system 10 a that are the same as those of the onboardnetwork system 10 are denoted in FIG. 20 by the same symbols as in FIG.2, and description hereof will be omitted here. Note that pointsregarding the onboard network system 10 a that are not described inparticular here are the same as with the onboard network system 10.

C-ECUs 500 a through 500 c are connected to the bus 30 a in a controlsystem network 1 a, and C-ECUs 500 d and 500 e are connected to the bus30 b. The C-ECUs 500 d and 500 e respectively are a door control ECUdirectly connected to a door open/close sensor and a window control ECUdirectly connected to a window open/close sensor or the like, forexample.

Besides having the functions of the hub 200, the hub 200 a alsofunctions as a CAN gateway, having a function of transferring a CANframe received from one CAN bus to the other CAN bus. The C-ECUs 500 athrough 500 e communicate with each other via the bus 30 a, bus 30 b,and hub 200 a, for example, and exchange frames following the CANprotocol.

The hub 200 a has the same configuration as the hub 200 illustrated inthe first embodiment (see FIG. 7). However, the degree-of-prioritysetting unit 260 of the hub 200 a is capable of updating the contents ofpriority information on the fly, in accordance with the state of thevehicle 9. For example, the degree-of-priority setting unit 260 updatesthe priority information in accordance with whether the vehicle 9 istraveling or stopped, based on priority control information illustratedin FIG. 21. Specifically, if the vehicle traveling state (travelingstate of the vehicle 9) is a traveling state, the degree of priority ofthe control system data reception buffer and control system datatransmission buffer is raised, and if the vehicle traveling state is astopped state, the degree of priority of the information system datareception buffer and information system data transmission buffer israised conversely. That is to say, the priority transmission buffer isthe transmission buffer 240 a (control system data transmission buffer)while the vehicle 9 is traveling, and is the transmission buffer 240 b(information system data transmission buffer) when the vehicle 9 isstopped, for example. The hub 200 a can distinguish whether the vehicletraveling state is traveling or stopped, from the contents (e.g.,vehicle state data) of CAN frames received from one of the C-ECUs. In astopped state, the vehicle speed is zero, for example. The data transferprocessing by the hub 200 a is the same as the data transfer processingby the hub 200 other than the point of being performed based on priorityinformation that is updated on the fly. (see FIG. 10 and FIGS. 12through 15).

Note that the hub 200 a may be connected to multiple Ethernet(registered trademark) cables as transmission paths of the informationsystem network 2, and may encompass functions the same as with the E-hub400 in the first embodiment.

2.2 Communication Sequence Related to Transfer Functions of Hub 200 a

FIG. 22 illustrates an example of a communication sequence related totransfer functions of the hub 200 a. The transfer rule information thatthe hub 200 a stores indicates that CAN frames of vehicle state datareceived from the bus 30 a should be transferred to the bus 30 b (CANbus 2) in this example.

Upon the vehicle 9 starting traveling, for example, the hub 200 a setspriority information at the degree-of-priority setting unit 260 so thatthe object of priority is control system data (step S1021). Accordingly,the degree of priority of the control system data reception buffer (orcontrol system data transmission buffer) is set higher than theinformation system data reception buffer (or information system datatransmission buffer) in the priority information.

The hub 200 a receives an E-frame containing sensor information from theinformation system network 2 (step S1022), and receives a CAN framecontaining vehicle state data from the bus 30 a (CAN bus 1), forexample, of the control system network 1 a (step S1023). The hub 200 athen confirms the reception buffers 220 a and 220 b, and reads outvehicle state data from the reception buffer 220 a with priority. Thehub 200 a selects the bus 30 b of the control system network 1 a as thedestination of the vehicle state data read out from the receptionbuffer, and transmits a CAN frame including that vehicle state data tothe bus 30 b of the control system network 1 a (step S1024). The hub 200a also receives a CAN frame including vehicle state data from the bus 30a of the control system network 1 a (step S1025).

The hub 200 a confirms the reception buffers 220 a and 220 b, reads outvehicle state data from the reception buffer 220 a with priority, and inthe same way selects the bus 30 b of the control system network 1 a asthe destination, and transmits a CAN frame including that vehicle statedata to the bus 30 b of the control system network 1 a (step S1026).

The hub 200 a confirms the reception buffers 220 a and 220 b, and sincethere is no data in the reception buffer 220 a, reads out the sensorinformation from the reception buffer 220 b. An assumption will be madehere that the transfer rule information indicates this sensorinformation has one device on the information system network 2 as thetransmission source, and another device as a destination. The hub 200 athen selects the information system network 2 as the destination of thesensor information that has been read out, and transmits an E-frame thatincludes the sensor information in the payload had and the MAC addressof the destination device as the destination MAC address, to theinformation system network 2 (step S1027).

2.3 Advantages of Second Embodiment

In the onboard network system 10 a according to the second embodiment,when transferring data, the hub 200 a connected to both of the firstnetwork (control system network 1 a) and second network (informationsystem network 2) that have different communication protocols from eachother reads out data from the reception buffer from one network withpriority in accordance with priority information that can be updated onthe fly based on the state of the vehicle 9, or performs transmissionwith priority from the transmission buffer for data of which thedestination is one network. Accordingly, the order of priority forprocessing based on data readout or transmission processing or the likecan be correlated with the importance of data transmitted over thenetworks. As a specific example, transmission of control system datarelating to traveling control of the vehicle 9 is given priority overtransmission of information system data such as image data or the likewhile the vehicle 9 is traveling, so a situation where transmission ofinformation system data adversely affects safe traveling of the vehicle9 or the like can be prevented. Conversely, when the vehicle 9 isstopped, transmission of information system data is given priority, soinformation and the like that has relatively large data amounts, such asimages and so forth, can be provided to the passenger (user) of thevehicle 9 without delay, and improve the comfort of the user.

In the same way as the hub 200 a, the degree-of-priority setting unit160 may update the priority information in accordance with the state ofthe vehicle 9 in the X-ECU 100 as well. Accordingly, if the travelingstate of the vehicle 9 on the fly is a traveling state, the degree ofpriority of the control system data reception buffer and control systemdata transmission buffer is raised in the priority information of theX-ECU 100, and if the vehicle traveling state is a stopped state, thedegree of priority of the information system data reception buffer andinformation system data transmission buffer is set to be raisedconversely. That is to say, the priority reception buffer is the controlsystem data reception buffer while the vehicle 9 is traveling, and isthe information system data reception buffer when the vehicle 9 isstopped. Also, the priority type data is the control system data whilethe vehicle 9 is traveling, and is information system data while thevehicle 9 is stopped.

Other Embodiments

The first and second embodiments serving as exemplary illustrations oftechnology relating to the present disclosure have been described above.However, the technology relating to the present disclosure is notrestricted to these, and embodiments where modification, substitution,omission, and so forth has been made as appropriate are also applicable.For example, the following modifications are also included in anembodiment of the present disclosure.

(1) The configurations of the onboard network systems 10 and 10 aillustrated in the above-described embodiments (see FIGS. 2 and 20) areonly examples, and any configuration may be made as long as it includesa first network where a first-type frame (e.g., CAN frame) relating totraveling control of a vehicle is transmitted over a bus following afirst communication protocol (e.g., CAN protocol) and a second networkwhere a second-type frame (e.g., E-frame) is transmitted following asecond communication protocol (e.g., Ethernet (registered trademark)protocol) that is different form the first communication protocol. Theconfiguration of the onboard network system may be such as modificationsillustrated in FIGS. 23 through 28 (modifications 1 through 6), forexample. The same components are denoted by the same reference symbolsin the drawings. An onboard network system 10 b illustrated in FIG. 23has a configuration where the X-ECU 100 is omitted from the onboardnetwork system 10. Note that the E-ECU 300 a may have ADAS functions,for example. The E-ECU 300 a and C-ECUs 500 a through 500 c in theonboard network system 10 b are capable of exchanging information witheach other via the hub 200, even without corresponding to two types ofcommunication protocols as with the X-ECU 100. In an onboard networksystem 10 c illustrated in FIG. 24, a gateway 600 does not have aninterface compatible with the Ethernet (registered trademark) protocol,and has functions of a CAN gateway that handles transfer of CAN framesbetween buses (CAN busses) 30 a and 30 c serving as transmission pathson a control system network 1 b. A hub 200 b has the function ofconnecting the control system network 1 b and an information systemnetwork 2 a, and relaying (transferring) data between the networks. Thehub 200 b has ports (connection terminals) connected to multipleEthernet (registered trademark) cables, and encompasses the samefunctions as the hub 200 and the E-hub 400 illustrated in the firstembodiment. An onboard network system 10 d illustrated in FIG. 25primarily is equivalent to an arrangement where the control systemnetwork 1 b in the onboard network system 10 c has been replaced by thecontrol system network 1 in the onboard network system 10. An onboardnetwork system 10 e illustrated in FIG. 26 is the onboard network system10 where the information system network 2 has been replaced by abus-type information system network 2 b. A hub 200 c is connected to thebus 30 a of the control system network 1 and a bus 20 x of theinformation system network 2 b, and has a function of transferring databetween two networks, in the same way as the hub 200. An X-ECU 100 a hasa communication interface that is compatible with both the controlsystem network 1 and the information system network 2 b, and isconnected to the bus 30 a of the control system network 1 and the bus 20x of the information system network 2 b. The X-ECU 100 a can receivedata from both networks in the same way as the X-ECU 100, and cantransmit data to both networks. The X-ECU 100 a has communicationinterfaces compatible with both networks, and accordingly can exchangedata more speedily than exchanging data with one of the networks via thehub 200 c. An onboard network system 10 f illustrated in FIG. 27 is anarrangement where the control system network 1 of the onboard networksystem 10 e has been replaced by the control system network 1 b, and thehub 200 c has been replaced by a hub 200 d connected to multiple CANbusses (busses 30 a and 30 c) of the control system network 1 b. The hub200 d has the same functions as the hub 200 c, and functions of a CANgateway. An onboard network system 10 g illustrated in FIG. 28 is anarrangement where the information system network 2 b in the onboardnetwork system 10 e has been replaced by an information system network 2c, and the hub 200 c has been replaced by a hub 200 e that connects tomultiple busses (busses 20 x and 20 y) of the information system network2 b. The hub 200 e encompasses the same functions as the hub 200 c, andframe relay functions of the information system network 2 c. Note thatthe external communication device 92 may be omitted from theabove-described onboard network systems, and the devices (sensors, etc.)connected to the transmission path of the information system networksand C-ECUs connected to the transmission path of the control systemnetworks may have any functions. An arrangement may be made where thenetwork hubs (hub) in the onboard network systems, such as the E-hub400, hub 200 b, and so forth, do not have functions as an Ethernet(registered trademark) switch (switching hub), and at the time oftransmitting E-frames, send out the E-frames onto all Ethernet(registered trademark) cables connected to the hub withoutdistinguishing the destination MAC addresses of the E-frames. Theconnection state of the information system network (network topology)may be changed in the above-described onboard network systems.

(2) Although the X-ECU 100 has been described in the embodiments aboveas having ADAS functions, the X-ECU 100 may have other functions insteadof having ADAS functions. The generating unit 130 of the X-ECU 100 mayadd information indicating the degree of priority of transmission toserve as a reference for priority transmission control (e.g., anumerical value indicating the degree of priority, informationindicating that priority is to be given, etc.) to data stored in thetransmission buffer 140 a or transmission buffer 140 b. The transmissionunit 150 may perform priority transmission control, such as transmittingearlier the higher the degree of priority is, based on the degree ofpriority of transmission of data stored in the buffers. The X-ECU 100may transmit the data with information indicating this degree ofpriority of transmission added thereto, included in the contents of CANframes or E-frames, and the hub 200 or the like may reference the degreeof priority of transmission and perform control to transfer withpriority (e.g., reading out and transmitting earlier the higher thedegree of priority of transmission is, etc.), for example. The X-ECU 100may be connected to each of the control system network and informationsystem network via a device having gateway functions or the like (arelay device such as a hub or the like).

(3) Description has been made in the above embodiments that the onboardnetwork system includes a first network (control system network) and asecond network (information system network), with the first networktransmitting CAN frames (data frames) over a CAN bus following the CANprotocol, and the second network transmitting E-frames (Ethernet(registered trademark) frames) following the Ethernet (registeredtrademark) protocol. This CAN protocol is to be understood to have abroad meaning, encompassing derivative protocols such as CANOpen used inembedded systems within automation systems and so forth, TTCAN(Time-Triggered CAN), CANFD (CAN with Flexible Data Rate) and so forth.Data frames in the CAN protocol may be in an extended ID format, besidesin the standard ID format. Ethernet (registered trademark) frames may beEthernet (registered trademark) Version 2 frames, or may be framesstipulated by IEEE 802.3. The Ethernet (registered trademark) protocolmay be understood to have a broad meaning, encompassing derivativeprotocols such as Ethernet (registered trademark) Audio Video Bridging(AVB) relating to IEEE 802.1, Ethernet (registered trademark) TimeSensitive Networking (TSN) relating to IEEE 802.1, Ethernet (registeredtrademark)/Industrial Protocol (IP), Ethernet (registered trademark) forControl Automation Technology (EtherCAT (registered trademark)), and soforth. An arrangement may be made where the first network transmitsfirst-type frames (e.g., CAN frames or the like) following a firstcommunication protocol, and the second network transmits second-typeframes (e.g., E-frames or the like) following a second communicationprotocol that differs from the first communication protocol. In thiscase, the first communication protocol is the CAN protocol for example,but is not restricted to the CAN protocol, and may be Local InterconnectNetwork (LIN), Media Oriented Systems Transport (MOST (registeredtrademark)), FlexRay (registered trademark), and so forth. Also, thesecond communication protocol is the Ethernet (registered trademark)protocol for example, but is not restricted to the Ethernet (registeredtrademark) protocol, and may be a BroadR-Reach protocol, for example.According to the onboard network system having the first network andsecond network, information transmitted from an ECU or the likeconnected to the first network (e.g., C-ECU) can be transmitted to anECU or the like connected to the second network (e.g., an E-ECU), viathe above-described hub or the like, and conversely, informationtransmitted by an ECU or the like connected to the second network can betransmitted to an ECU or the like connected to the first network. Notethat the Ethernet (registered trademark) illustrated in theabove-described embodiments can transmit a great amount of data perframe as compared to CAN. With regard to this point, the secondcommunication protocol may be various types of protocols that cantransmit a great amount of data per frame as compared to the firstcommunication protocol.

(4) The contents of CAN frames and E-frames stored in the receptionbuffers (reception buffers 120 a, 120 b, 220 a, 220 b) illustrated inthe above-described embodiments are not restricted to data (contents ofthe data field of CAN frames or contents of the payload of Ethernet(registered trademark) frames), and the contents may include informationof any portion of CAN frames or E-frames. Data stored in transmissionbuffers (transmission buffers 140 a, 140 b, 240 a, 240 b) may also bedata equivalent to the contents of entire CAN frames or E-frames to betransmitted. Thus, even in a case where the contents of entire CANframes to be transmitted are stored in the transmission buffers, if anabnormality occurs at part of the CAN control system network, thetransmission units 150 and 250 can construct E-frames including thecontents of the CAN frames in the payload and so forth, and transmit tothe information system network.

(5) The order of executing the procedures of various types of processingillustrated in the above-described embodiments (e.g., the proceduresillustrated in FIGS. 9 through 19, etc.) is not necessarily restrictedto the above-described order, and the order of execution may be switchedaround, multiple procedures may be executed in parallel, part of theprocedures may be omitted, and so forth, without departing from theessence of the disclosure.

(6) Devices in the above-described embodiments, such as hubs, E-hubs,ECUs (E-ECUs, C-ECUs, and X-ECUs), and so forth, may include otherhardware components such as a hard disk device, display, keyboard,mouse, and so forth. The functions of the device may be realized throughsoftware by programs stored in memory being executed by a processor, orthe functions may be realized by dedicated hardware (digital circuits orthe like). Assignation of functions among the components within thedevice is changeable.

(7) The hubs (e.g., hub 200, etc.) illustrated in the above-describedembodiments may effect control where data that is read out from apriority reception buffer with priority is immediately transferred, byreferencing information indicating the degree of priority relating toreception buffers in priority information, instated of referencinginformation indicating the degree of priority relating to transmissionbuffers, for example. That is to say, a hub connected to a bus of afirst network and to a second network in an onboard network system thatincludes the first network where transmission of first-type framesrelating to traveling control of a vehicle is performed over a busfollowing a first communication protocol, and the second network wheretransmission of second-type frames is performed following a secondcommunication protocol that is different from the first communicationprotocol, includes a first reception buffer, a second reception buffer,a first reception unit that sequentially receives the first-type framesfrom the bus and stores data within the first-type frames in the firstreception buffer, a second reception unit that sequentially receives thesecond-type frames from the second network and stores data within thesecond-type frames in the second reception buffer, a selecting unit thatselects whether the destination of data read out from one of the firstreception buffer and the second reception buffer is the first network orthe second network, and a transmission unit that transmits a frameincluding this data to the destination when the selecting unit selectsthe destination of the data, the selecting unit performing priorityreadout control so as to read out unread data in the priority receptionbuffer that is one of the first reception buffer and second receptionbuffer with priority over unread data in the non-priority receptionbuffer that is the other. According to this hub, transmission of datacan be appropriately performed by priority readout control, byappropriately setting the priority reception buffer taking theproperties of the first network and the second network each intoconsideration.

(8) Part or all of the components configuring the devices in theabove-described embodiments may be configured as a single system largescale integration (LSI). A system LSI is a super-multi-functional LSImanufactured integrating multiple components on a single chip, andspecifically is a computer system configured including a microprocessor,ROM, RAM, and so forth. A computer program is recorded in the RAM. Thesystem LSI realizes its functions by the microprocessor operatingaccording to the computer program. The parts of the components making upthe above devices may be individually formed into one chip, or part orall may be included in one chip. While description has been maderegarding a system LSI, there are different names such as IC, LSI, superLSI, and ultra LSI, depending on the degree of integration. The circuitintegration technique is not restricted to LSIs, and dedicated circuitsor general-purpose processors may be used to realize the same. A fieldprogrammable gate array (FPGA) which can be programmed aftermanufacturing the LSI, or a reconfigurable processor where circuit cellconnections and settings within the LSI can be reconfigured, may beused. Further, in the event of the advent of an integrated circuittechnology which would replace LSIs by advance of semiconductortechnology or a separate technology derived therefrom, such a technologymay be used for integration of the functional blocks, as a matter ofcourse. Application of biotechnology and so forth is a possibility.

(9) Part or all of the components of which the above-described devicesare configured may be configured as an IC card detachably mountable toeach device or a standalone module. The IC card or module is a computersystem configured including a microprocessor, ROM, RAM, and so forth.The IC card or module may include the above-describedsuper-multifunctional LSI. The IC card or module achieves its functionsby the microprocessor operating according to the computer program. TheIC card or module may be tamper-resistant.

(10) One aspect of the present disclosure may be a communication methodor transfer method including all or part of the processing proceduresillustrated in FIGS. 9 through 19, for example. For example, thecommunication method is a method used by an ECU (e.g., X-ECU 100)connected to a bus of a first network and to a second network in anonboard network system that includes the first network wheretransmission of first-type frames (e.g., CAN frames) relating totraveling control of a vehicle is performed over a bus following a firstcommunication protocol (e.g., CAN), and the second network wheretransmission of second-type frames (e.g., E-frames) is performedfollowing a second communication protocol (e.g., Ethernet (registeredtrademark)) that is different from the first communication protocol, theECU including a first reception buffer (reception buffer 120 a), asecond reception buffer (reception buffer 120 b), a first transmissionbuffer (transmission buffer 140 a), and a second transmission buffer(transmission buffer 140 b). The method includes a first reception stepof sequentially receiving first-type frames from the bus and storingdata within the first-type frames in a first reception buffer (e.g.,processing by the reception unit 110 a), a second reception step ofsequentially receiving second-type frames from the second network andstoring data within the second-type frames in a second reception buffer(e.g., processing by the reception unit 110 b), a generating step ofsequentially generating first-type data (e.g., control system data) thatis data for traveling control of the vehicle, and second-type data(information system data) that is data used for other than travelingcontrol of the vehicle, by referencing the contents of the firstreception buffer and the second reception buffer, storing the generatedfirst-type data in the first transmission buffer, and storing thegenerated second-type data in the second transmission buffer (e.g.,steps S1 and S2), and a transmission step of transmittingyet-to-be-transmitted first-type data in the first transmission bufferand yet-to-be-transmitted second-type data in the second transmissionbuffer (e.g., step S3). In the transmission step, priority transmissioncontrol is performed where priority type data, which is one of thefirst-type data and second-type data, is transmitted with priority overnon-priority type data that is the other. Also, for example, thetransfer method is a method used by a hub (e.g., hub 200, etc.)connected to a bus of a first network and to a second network in anonboard network system that includes the first network wheretransmission of first-type frames relating to traveling control of avehicle is performed over a bus following a first communicationprotocol, and the second network where transmission of second-typeframes is performed following a second communication protocol that isdifferent from the first communication protocol, the hub including afirst reception buffer (reception buffer 220 a), a second receptionbuffer (reception buffer 220 b), a first transmission buffer(transmission buffer 240 a), and a second transmission buffer(transmission buffer 240 b). The method includes a first reception stepof sequentially receiving first-type frames from the bus and storingdata within the first-type frames in a first reception buffer (e.g.,processing by the reception unit 210 a), a second reception step ofsequentially receiving second-type frames from the second network andstoring data within the second-type frames in a second reception buffer(e.g., processing by the reception unit 210 b), a selecting step ofselecting the first network or the second network as the destination ofthe data of that is the contents of one of the first reception bufferand the second reception buffer, storing the data in the firsttransmission buffer in a case of having selected the first network, andstoring the data in the second transmission buffer in a case of havingselected the second network (e.g., steps S1 and S4), and a transmissionstep of transmitting yet-to-be-transmitted data in the firsttransmission buffer and yet-to-be-transmitted data in the secondtransmission buffer (e.g., step S3). In the transmission step, prioritytransmission control is performed where yet-to-be-transmitted data in apriority transmission buffer that is one of the first transmissionbuffer and the second transmission buffer, is transmitted with priorityover yet-to-be-transmitted data in a non-priority transmission bufferthat is the other. The method may be a program (computer program) whichrealizes this method by a computer, or may be digital signals made up ofthe computer program. An aspect of the present disclosure may be thecomputer program or the digital signals recorded in a computer-readablerecording medium, such as for example, a flexible disk, a hard disk, aCD-ROM, MO, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray (registered trademark)Disc), semiconductor memory, or the like. The present disclosure mayalso be the digital signals recorded in these recording mediums. Anaspect of the present disclosure may be an arrangement where thecomputer program or the digital signals are transmitted over an electriccommunication line, wireless or cable communication line, a network ofwhich the Internet is representative, data broadcasting, or the like.Also, an aspect of the present disclosure may be a computer systemhaving a microprocessor and memory, where the memory records thecomputer program, and the microprocessor operates according to thecomputer program. The program or the digital signals may be recorded inthe recording medium and transported, or the program or the digitalsignals may be transported over the network or the like, and thereby beexecuted by another computer system that is independent.

(11) Forms realized by optionally combining the components and functionsdescribed in the above embodiments and the above modifications are alsoincluded in the scope of the present disclosure.

The present disclosure is applicable to onboard network systemsincluding onboard networks.

What is claimed is:
 1. A network hub connected to a first network and asecond network in an onboard network system, the onboard network systemincluding the first network to transmit first-type frames following afirst communication protocol, and the second network to transmitsecond-type frames following a second communication protocol, thenetwork hub comprising: a first reception buffer; a second receptionbuffer; a first transmission buffer; a second transmission buffer; afirst receiver that sequentially receives the first-type frames from thefirst network and stores data within the first-type frames in the firstreception buffer; a second receiver that sequentially receives thesecond-type frames from the second network and stores data within thesecond-type frames in the second reception buffer; a processor thatreads data stored in the first reception buffer or the second receptionbuffer, stores the data in the first transmission buffer when adestination for the data is in the first network, and stores the data inthe second transmission buffer when the destination for the data is inthe second network; and a transmitter that transmits first data in thefirst transmission buffer and second data in the second transmissionbuffer, wherein the transmitter performs priority transmission control,where priority data in a priority transmission buffer that is one of thefirst transmission buffer and the second transmission buffer istransmitted with priority over non-priority data in a non-prioritytransmission buffer that is another of the first transmission buffer andthe second transmission buffer.
 2. The network hub according to claim 1,wherein the priority transmission buffer is the first transmissionbuffer, wherein the transmitter performs transmission of the first datain the first transmission buffer by sending a first-type frame includingthe first data to the first network in a case where predeterminedexception conditions are not satisfied, and by sending a second-typeframe including the second data to the second network in a case wherethe predetermined exception conditions are satisfied, and wherein thetransmitter performs transmission of the second data in the secondtransmission buffer by sending a second-type frame including the seconddata to the second network.
 3. The network hub according to claim 2,wherein the predetermined exception conditions are conditions that aresatisfied when an abnormality is detected in a part of the firstnetwork.
 4. The network hub according to claim 1, wherein thetransmitter performs the priority transmission control by: repeatedlyconfirming the first transmission buffer and the second transmissionbuffer; transmitting the priority data in the priority transmissionbuffer in a case where the first data is in the first transmissionbuffer and the second data is in the second transmission buffer duringthe confirming; transmitting the first data in the first transmissionbuffer in a case where the first data is in the first transmissionbuffer and the second data is not in the second transmission bufferduring the confirming; and transmitting the second data in the secondtransmission buffer in a case where the first data is not in the firsttransmission buffer and the second data is in the second transmissionbuffer during the confirming.
 5. The network hub according to claim 1,wherein the transmitter performs the priority transmission control by:repeatedly confirming the first transmission buffer and the secondtransmission buffer; transmitting a predetermined quantity of thepriority data in the priority transmission buffer, and thereaftertransmitting one of the non-priority data in the non-prioritytransmission buffer, in a case where the first data is in the firsttransmission buffer and the second data is in the second transmissionbuffer during the confirming; transmitting the first data in the firsttransmission buffer in a case where the first data is in the firsttransmission buffer and the second data is not in the secondtransmission buffer during the confirming; and transmitting the seconddata in the second transmission buffer in a case where the first data isnot in the first transmission buffer and the second data is in thesecond transmission buffer during the confirming.
 6. The network hubaccording to claim 5, wherein the predetermined quantity of the prioritydata transmitted from the priority transmission buffer is apredetermined multiple of the non-priority data transmitted from thenon-priority transmission buffer.
 7. The network hub according to claim1, wherein the transmitter performs the priority transmission controlby: repeatedly confirming the first transmission buffer and the secondtransmission buffer; transmitting the priority data in the prioritytransmission buffer when a non-transmission time of the non-prioritydata in the non-priority transmission buffer does not exceed apredetermined threshold value, and transmitting the non-priority data inthe non-priority transmission buffer when the non-transmission timeexceeds the predetermined threshold value; transmitting the first datain the first transmission buffer in a case where the first data is inthe first transmission buffer and the second data is not in the secondtransmission buffer during the confirming; and transmitting the seconddata in the second transmission buffer in a case where the first data isnot in the first transmission buffer and the second data is in thesecond transmission buffer during the confirming.
 8. The network hubaccording to claim 1, wherein the processor performs priority readoutcontrol for reading the data stored in the first reception buffer or thesecond reception buffer, where data stored in a priority receptionbuffer that is one of the first reception buffer and the secondreception buffer is read with priority over data stored in anon-priority reception buffer that is another of the first transmissionbuffer and the second transmission buffer, wherein, in a case where thepriority transmission buffer is the first transmission buffer, thepriority reception buffer is the first reception buffer, and wherein, ina case where the priority transmission buffer is the second transmissionbuffer, the priority reception buffer is the second reception buffer. 9.The network hub according to claim 8, wherein the processor performs thepriority readout control by: repeatedly confirming the first receptionbuffer and the second reception buffer; reading priority data in thepriority reception buffer out of the first reception buffer and thesecond reception buffer in a case where first data is in the firstreception buffer and second data is in the second reception bufferduring the confirming; reading the first data in the first receptionbuffer in a case where the first data is in the first reception bufferand the second data is not in the second reception buffer during theconfirming; and reading the second data in the second reception bufferin a case where the first data is not in the first reception buffer andthe second data is in the second reception buffer during the confirming.10. The network hub according to claim 8, wherein the processor performsthe priority readout control by: repeatedly confirming the firstreception buffer and the second reception buffer; reading apredetermined quantity of priority data in the priority reception bufferout of the first reception buffer and the second reception buffer, andthereafter reading one non-priority data in the non-priority receptionbuffer, in a case where first data is in the first reception buffer andsecond data is in the second reception buffer during the confirming;reading the first data in the first reception buffer in a case where thefirst data is in the first reception buffer and the second data is notin the second reception buffer during the confirming; and reading thesecond data in the second reception buffer in a case where the firstdata is not in the first reception buffer and the second data is in thesecond reception buffer during the confirming.
 11. The network hubaccording to claim 10, wherein the predetermined quantity of thepriority data is a predetermined multiple of the non-priority data. 12.The network hub according to claim 8, wherein the processor performs thepriority readout control by: repeatedly confirming the first receptionbuffer and the second reception buffer; reading priority data in thepriority reception buffer when a non-readout time of non-priority datain the non-priority reception buffer does not exceed a predeterminedthreshold value, and reading the non-priority data in the non-priorityreception buffer when the non-readout time exceeds the predeterminedthreshold value, in a case where first data is in the first receptionbuffer and second data is in the second reception buffer during theconfirming; reading the first data in the first reception buffer in acase where the first data is in the first reception buffer and thesecond data is not in the second reception buffer during the confirming;and reading the second data in the second reception buffer in a casewhere the first data is not in the first reception buffer and the seconddata is in the second reception buffer during the confirming.
 13. Thenetwork hub according to claim 1, wherein, in a case where thedestination for the data that is the content of the second receptionbuffer is the first network, the processor splits the data into aplurality of data, and stores the plurality of data in the firsttransmission buffer.
 14. The network hub according to claim 1, whereinthe first communication protocol is the CAN (Controller Area Network)protocol, wherein the second communication protocol is the Ethernet(registered trademark) protocol, wherein the first-type frames are dataframes, and wherein the second-type frames are Ethernet (registeredtrademark) frames.
 15. The network hub unit according to claim 1,wherein a maximum data amount of the second-type frames following thesecond communication protocol is greater than a maximum data amount ofthe first-type frames following the first communication protocol. 16.The network hub according to claim 1, wherein the priority transmissionbuffer is the first transmission buffer while the vehicle is traveling,and is the second transmission buffer while the vehicle is stopped. 17.A transfer method for a network hub connected to a first network and asecond network in an onboard network system, the onboard network systemincluding the first network to transmit first-type frames following afirst communication protocol, and the second network to transmitsecond-type frames following a second communication protocol that isdifferent from the first communication protocol, the network hubincluding a first reception buffer, a second reception buffer, a firsttransmission buffer, and a second transmission buffer, the transfermethod comprising: sequentially receiving the first-type frames from thefirst network and storing data within the first-type frames in the firstreception buffer; sequentially receiving the second-type frames from thesecond network and storing data within the second-type frames in thesecond reception buffer; reading data stored in the first receptionbuffer or the second reception buffer, storing the data in the firsttransmission buffer when a destination for the data is the firstnetwork, and storing the data in the second transmission buffer when thedestination for the data is in the second network; and transmittingfirst data in the first transmission buffer and second data in thesecond transmission buffer, wherein, in the transmitting, prioritytransmission control is performed, where priority data in a prioritytransmission buffer that is one of the first transmission buffer and thesecond transmission buffer is transmitted with priority overnon-priority data in a non-priority transmission buffer that is anotherof the first transmission buffer and the second transmission buffer. 18.An onboard network system comprising: a first network to transmitfirst-type frames following a first communication protocol; a secondnetwork to transmit second-type frames following a second communicationprotocol that is different from the first communication protocol; anelectronic control unit connected to the first network; an electroniccontrol unit connected to the second network; and a network hubconnected to the first network and the second network, wherein thenetwork hub includes: a first reception buffer; a second receptionbuffer; a first transmission buffer; a second transmission buffer; afirst receiver that sequentially receives the first-type frames from thefirst network and stores data within the first-type frames in the firstreception buffer; a second receiver that sequentially receives thesecond-type frames from the second network and stores data within thesecond-type frames in the second reception buffer; a processor thatreads data stored in the first reception buffer or the second receptionbuffer, stores the data in the first transmission buffer when adestination for the data is in the first network, and stores the data inthe second transmission buffer when the destination for the data is inthe second network; and a transmitter that transmits first data in thefirst transmission buffer and second data in the second transmissionbuffer, wherein the transmitter performs priority transmission control,where priority data in a priority transmission buffer that is one of thefirst transmission buffer and the second transmission buffer istransmitted with priority over non-priority data in a non-prioritytransmission buffer that is another of the first transmission buffer andthe second transmission buffer.